Prosthetic heart valve

ABSTRACT

Certain embodiments of the present disclosure provide a prosthetic valve (e.g., prosthetic heart valve) and a valve delivery apparatus for delivery of the prosthetic valve to a native valve site via the human vasculature. The prosthetic valve comprises a frame or stent that comprises multiple cells arranged in unique ways. The prosthetic valve also comprises a leaflet assembly coupled to the frame and having a plurality of leaflets, wherein the leaflets are configured to allow blood to flow through the prosthetic heart valve in one direction from an inflow end portion to an outflow end portion of the frame or stent.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.14/794,690, filed Jul. 8, 2015, which is a continuation of U.S.application Ser. No. 13/405,119, filed Feb. 24, 2012, which claims thebenefit of Provisional Application No. 61/446,972, filed Feb. 25, 2011,all of which are incorporated herein by reference.

FIELD

The present invention concerns embodiments of a prosthetic valve (e.g.,prosthetic heart valve) and a delivery apparatus for implanting aprosthetic valve.

BACKGROUND

Prosthetic cardiac valves have been used for many years to treat cardiacvalvular disorders. The native heart valves (such as the aortic,pulmonary and mitral valves) serve critical functions in assuring theforward flow of an adequate supply of blood through the cardiovascularsystem. These heart valves can be rendered less effective by congenital,inflammatory or infectious conditions. Such damage to the valves canresult in serious cardiovascular compromise or death. For many years thedefinitive treatment for such disorders was the surgical repair orreplacement of the valve during open heart surgery, but such surgeriesare prone to many complications. More recently a transvascular techniquehas been developed for introducing and implanting a prosthetic heartvalve using a flexible catheter in a manner that is less invasive thanopen heart surgery.

In this technique, a prosthetic valve is mounted in a crimped state onthe end portion of a flexible catheter and advanced through a bloodvessel of the patient until the prosthetic valve reaches theimplantation site. The prosthetic valve at the catheter tip is thenexpanded to its functional size at the site of the defective nativevalve such as by inflating a balloon on which the prosthetic valve ismounted. Alternatively, the prosthetic valve can have a resilient,self-expanding stent or frame that expands the prosthetic valve to itsfunctional size when it is advanced from a delivery sheath at the distalend of the catheter.

Balloon-expandable prosthetic valves typically are preferred forreplacing calcified native valves because the catheter balloon can applysufficient expanding force to anchor the frame of the prosthetic valveto the surrounding calcified tissue. On the other hand, self-expandingprosthetic valves sometimes are preferred for replacing a defective,non-stenotic (non-calcified) native valve, although they also can beused to replace stenotic valves. One drawback associated with implantinga self-expanding prosthetic valve is that as the operator begins toadvance the prosthetic valve from the open end of the delivery sheath,the prosthetic valve tends to “jump” out very quickly from the end ofthe sheath; in other words, the outward biasing force of the prostheticvalve's frame tends to cause the prosthetic valve to be ejected veryquickly from the distal end of the delivery sheath, making it difficultto deliver the prosthetic valve from the sheath in a precise andcontrolled manner and increasing the risk of trauma to the patient.

Another problem associated with implanting a percutaneous prostheticvalve in a non-stenotic native valve is that the prosthetic valve maynot be able to exert sufficient force against the surrounding tissue toresist migration of the prosthetic valve. Typically, the stent of theprosthetic valve must be provided with additional anchoring orattachment devices to assist in anchoring the prosthetic valve to thesurrounding tissue. Moreover, such anchoring devices or portions of thestent that assist in anchoring the prosthetic valve typically extendinto and become fixed to non-diseased areas of the vasculature, whichcan result in complications if future intervention is required, forexample, if the prosthetic valve needs to be removed from the patient.

SUMMARY

Certain embodiments of the present disclosure provide a prosthetic valve(e.g., a prosthetic heart valve) and a valve delivery apparatus fordelivery of the prosthetic valve to a native valve site via the humanvasculature. The delivery apparatus is particularly suited for advancinga prosthetic valve through the aorta (i.e., in a retrograde approach)for replacing a diseased native aortic valve. The delivery apparatus inparticular embodiments is configured to deploy a prosthetic valve from adelivery sheath in a precise and controlled manner at the targetlocation within the body.

In one representative embodiment, a delivery apparatus for implanting aprosthetic valve comprises a first elongated shaft having a proximal endportion and a distal end portion, and a second elongated shaft extendingthrough the first shaft and having a proximal end portion and a distalend portion. The second shaft is rotatable relative to the first shaftbut is fixed against axial movement relative to the first shaft. Thedistal end portion of the second shaft has an outer surface comprisingexternal threads or grooves. A sheath retaining ring is disposed on thethreads or grooves of the second shaft and is fixed against rotationalmovement relative to the distal end portion of the second shaft. Adelivery sheath is configured to receive and retain a prosthetic valvein a compressed delivery state, the delivery sheath being connected tothe sheath retaining ring. The second shaft is configured to berotatable relative to the first shaft such that rotation of the secondshaft causes the sheath retaining ring to move axially along the threadsor grooves, thereby moving the sheath axially relative to the first andsecond shafts to deploy a prosthetic valve contained within the sheath.

In one implementation, the distal end portion of the second shaftcomprises a screw having external threads and the sheath retaining ringcomprises a nut having internal threads that engage the external threadson the screw. In another implementation, the distal end portion of thesecond shaft comprises a coil having external grooves and the sheathretaining ring comprises a washer that engages the grooves on the coil.

In another representative embodiment, a delivery apparatus forimplanting a prosthetic valve comprises a first elongated shaft having aproximal end portion and a distal end portion, and a second elongatedshaft extending through the first shaft and having a proximal endportion and a distal end portion. The second shaft is rotatable relativeto the first shaft but is desirably fixed against axial movementrelative to the first shaft. A third elongated shaft extends through thesecond shaft and has a proximal end portion and a distal end portion. Adelivery sheath coupled to the second shaft is configured to receive andretain a prosthetic valve in a compressed delivery state. The deliveryapparatus can further include a valve-retaining mechanism comprisingfirst and second components on the distal end portion of the third shaftand the distal end portion of the first shaft, respectively, the firstand second components cooperating to form a releasable connection with astent of the prosthetic valve. The second shaft is configured to berotatable relative to the first shaft such that rotation of the secondshaft causes the sheath to move axially relative to the first, secondand third shafts to deploy a prosthetic valve contained within thesheath. The valve-retaining mechanism prevents axial and rotationalmovement of the prosthetic valve relative to the first and third shaftsas the second shaft is rotated to move the sheath axially to deploy theprosthetic valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prosthetic valve that can be used toreplace the native aortic valve of the heart, according to oneembodiment.

FIG. 2 is a perspective view of a portion of the prosthetic valve ofFIG. 1 illustrating the connection of two leaflets to the support frameof the prosthetic valve.

FIG. 3 is side elevation view of the support frame of the prostheticvalve of FIG. 1.

FIG. 4 is a perspective view of the support frame of the prostheticvalve of FIG. 1.

FIG. 5A is a cross-sectional view of the heart showing the prostheticvalve of FIG. 1 implanted within the aortic annulus.

FIG. 5B is an enlarged view of FIG. 5A illustrating the prosthetic valveimplanted within the aortic annulus, shown with the leaflet structure ofthe prosthetic valve removed for clarity.

FIG. 6 is a perspective view of the leaflet structure of the prostheticvalve of FIG. 1 shown prior to being secured to the support frame.

FIG. 7 is a cross-sectional view of the prosthetic valve of FIG. 1.

FIG. 8 is a cross-sectional view of an embodiment of a deliveryapparatus that can be used to deliver and implant a prosthetic valve,such as the prosthetic valve shown in FIG. 1.

FIGS. 8A-8C are enlarged cross-sectional views of sections of FIG. 8.

FIG. 9 is an exploded view of the delivery apparatus of FIG. 8.

FIG. 10 is a side view of the guide catheter of the delivery apparatusof FIG. 8.

FIG. 11 is a perspective, exploded view of the proximal end portion ofthe guide catheter of FIG. 10.

FIG. 12 is a perspective, exploded view of the distal end portion of theguide catheter of FIG. 10.

FIG. 13 is a side view of the torque shaft catheter of the deliveryapparatus of FIG. 8.

FIG. 14 is an enlarged side view of the rotatable screw of the torqueshaft catheter of FIG. 13.

FIG. 15 is an enlarged perspective view of a coupling member disposed atthe end of the torque shaft.

FIG. 16 is an enlarged perspective view of the threaded nut used in thetorque shaft catheter of FIG. 13.

FIG. 17 is an enlarged side view of the distal end portion of the nosecone catheter of the delivery apparatus of FIG. 8.

FIG. 17A is an enlarged, cross-sectional view of the nose cone of thecatheter shown FIG. 17.

FIG. 17B is an enlarged cross-sectional view of the distal end portionof the delivery apparatus of FIG. 8 showing the stent of a prostheticvalve retained in a compressed state within a delivery sheath.

FIG. 18 is an enlarged side view of the distal end portion of thedelivery apparatus of FIG. 8 showing the delivery sheath in a deliveryposition covering a prosthetic valve in a compressed state for deliveryinto a patient.

FIG. 19 is an enlarged cross-sectional view of a section of the distalend portion of the delivery apparatus of FIG. 8 showing thevalve-retaining mechanism securing the stent of a prosthetic valve tothe delivery apparatus.

FIG. 20 is an enlarged cross-sectional view similar to FIG. 19, showingthe inner fork of the valve-retaining mechanism in a release positionfor releasing the prosthetic valve from the delivery apparatus.

FIGS. 21 and 22 are enlarged side views of distal end portion of thedelivery apparatus of FIG. 8, illustrating the operation of the torqueshaft for deploying a prosthetic valve from a delivery sheath.

FIGS. 23-26 are various views of an embodiment of a motorized deliveryapparatus that can be used to operate the torque shaft of the deliveryapparatus shown in FIG. 8.

FIG. 27 is a perspective view of an alternative motor that can be usedto operate the torque shaft of the delivery apparatus shown in FIG. 8.

FIG. 28A is an enlarged view of a distal segment of the guide cathetershaft of FIG. 10.

FIG. 28B shows the cut pattern for forming the portion of the shaftshown in FIG. 28A, such as by laser cutting a metal tube.

FIG. 29A is an enlarged view of a distal segment of a guide cathetershaft, according to another embodiment.

FIG. 29B shows the cut pattern for forming the shaft of FIG. 29A, suchas by laser cutting a metal tube.

FIG. 30 is a side view of the distal end portion of another embodimentof a delivery apparatus.

FIG. 31 is a side view similar to FIG. 30 showing the sheath of thedelivery apparatus in a partially retracted position.

FIG. 32 is a side view similar to FIG. 30 shown with the sheath removedfor purposes of illustration.

FIG. 33 is a side view similar to FIG. 32 showing a portion of thedelivery apparatus in a bent position. This figure illustrates that thedelivery apparatus can exhibit sufficient flexibility along the portioncontaining the screw mechanism.

FIG. 34 is a perspective view of the handle portion of the deliveryapparatus shown in FIG. 30, according to one embodiment.

FIG. 35 is a perspective view illustrating the inside of the handleportion.

FIG. 36 is a side view illustrating the deployment of a prosthetic valvefrom the sheath of the delivery apparatus of FIG. 30.

FIG. 37 is a side view illustrating the operation of the valve-retainingmechanism of the delivery apparatus of FIG. 30.

FIG. 38 is a side view of a modified valve-retaining mechanism,according to one embodiment.

FIG. 39 is a side view of a modified valve-retaining mechanism,according to another embodiment.

FIG. 40 is a side view of a section of a torque shaft that can be usedin a delivery apparatus, according to one embodiment.

FIG. 40A is an enlarged view of a section of the torque shaft shown inFIG. 40.

FIG. 41 shows the cut pattern for forming the torque shaft of FIG. 40,such as by laser cutting a metal tube.

FIGS. 42-45 illustrate a loading cone and method of using the loadingcone to load a prosthetic valve into the sheath of a delivery apparatus(e.g., the delivery apparatus of FIG. 8), according to one embodiment.

FIG. 46 is a perspective view of an alternative embodiment of a loadingcone.

FIGS. 47-48 show an alternative embodiment of a sheath of a deliveryapparatus.

FIG. 49 shows the deployment of a prosthetic valve from the sheath shownin FIGS. 47-48.

FIG. 50 is a perspective view of another embodiment of a sheath of adelivery apparatus.

FIG. 51 is a perspective view of a loading cone and plunger assembly forloading a prosthetic valve into a delivery sheath, according to anotherembodiment.

FIG. 52 is a perspective view of an alternative embodiment of theloading cone of FIG. 51.

FIGS. 53-57 are side views of the distal end portions of five additionalembodiments of delivery apparatuses.

FIG. 58A is a perspective view of an introducer sheath, according toanother embodiment.

FIG. 58B is an enlarged, perspective view of the sleeve of theintroducer sheath of FIG. 58A.

FIG. 59 is an enlarged, perspective view of another embodiment of asleeve that can be used with the introducer sheath of FIG. 58A.

FIG. 60 is an end view of a sleeve that can be used with the introducersheath of FIG. 58A.

FIG. 61 is a perspective view of a segment of a sleeve of an introducersheath, according to another embodiment.

FIG. 62 is a side elevation view of a metal sleeve for an introducersheath, according to another embodiment.

FIG. 63 shows the cut pattern for forming the metal sleeve of FIG. 61.

FIG. 64 shows the cut pattern for forming the metal sleeve of FIG. 62.

FIG. 65 shows a cut pattern similar to FIG. 64 but having narrowerapertures.

FIG. 66 is a front elevation view of a wire coil and washer assemblythat can be incorporated in a torque shaft in place of the screw and nutassembly shown in FIG. 13.

FIG. 67 is a side view of the wire coil and washer assembly of FIG. 66shown partially in section.

FIGS. 68-72 are flattened views of various embodiments of stents forprosthetic heart valves.

FIG. 73 is a perspective view of a storage tube assembly for storing aprosthetic valve in a partially crimped state, according to oneembodiment.

FIG. 74 is an exploded, perspective view of the storage tube assembly ofFIG. 73

FIG. 75 is an exploded, cross-sectional view of the storage tubeassembly of FIG. 75.

FIG. 76 is a side elevation view of a prosthetic valve transfer tube,according to one embodiment, that can be used to transfer a partiallycrimped prosthetic valve into a storage tube.

FIG. 77 is a cross-sectional view of the transfer tube of FIG. 76.

FIG. 78 is a perspective view of an attachment spacer device that can beused in connecting a prosthetic valve to a delivery apparatus.

FIG. 79 is a side elevation view of the attachment spacer device of FIG.78.

FIG. 80 is a cross-sectional view taken along line 80-80 of FIG. 79.

FIG. 81 is an exploded, perspective view of a valve attachment tool,according to one embodiment, that can be used to secure a prostheticvalve to a delivery apparatus.

FIGS. 82 and 83 are elevation views showing the outside and insidesurfaces, respectively, of a housing portion of the valve attachmenttool shown in FIG. 81.

FIG. 84 is a cross-sectional view of a valve plunger, according to oneembodiment, that is adapted to be used with the attachment tool of FIG.81.

FIG. 85 is a bottom plan view of the valve plunger of FIG. 84.

FIGS. 86 and 87 are side and cross-sectional views, respectively, of aprotective sleeve or tube adapted to be used with the valve plunger ofFIG. 84.

FIGS. 88-101 are various views illustrating an exemplary method forattaching a prosthetic valve to a delivery apparatus.

FIGS. 102-113 are various views illustrating an exemplary method forpartially crimping a prosthetic valve for storage and eventual use.

DETAILED DESCRIPTION

Referring first to FIG. 1, there is shown a prosthetic aortic heartvalve 10, according to one embodiment. The prosthetic valve 10 includesan expandable frame member, or stent, 12 that supports a flexibleleaflet section 14. The prosthetic valve 10 is radially compressible toa compressed state for delivery through the body to a deployment siteand expandable to its functional size shown in FIG. 1 at the deploymentsite. In certain embodiments, the prosthetic valve 10 is self-expanding;that is, the prosthetic valve can radially expand to its functional sizewhen advanced from the distal end of a delivery sheath. Apparatusesparticularly suited for percutaneous delivery and implantation of aself-expanding prosthetic valve are described in detail below. In otherembodiments, the prosthetic valve can be a balloon-expandable prostheticvalve that can be adapted to be mounted in a compressed state on theballoon of a delivery catheter. The prosthetic valve can be expanded toits functional size at a deployment site by inflating the balloon, asknown in the art.

The illustrated prosthetic valve 10 is adapted to be deployed in thenative aortic annulus, although it also can be used to replace the othernative valves of the heart. Moreover, the prosthetic valve 10 can beadapted to replace other valves within the body, such venous valves.

FIGS. 3 and 4 show the stent 12 without the leaflet section 14 forpurposes of illustration. As shown, the stent 12 can be formed from aplurality of longitudinally extending, generally sinusoidal shaped framemembers, or struts, 16. The struts 16 are formed with alternating bendsand are welded or otherwise secured to each other at nodes 18 formedfrom the vertices of adjacent bends so as to form a mesh structure. Thestruts 16 can be made of a suitable shape memory material, such as thenickel titanium alloy known as Nitinol, that allows the prosthetic valveto be compressed to a reduced diameter for delivery in a deliveryapparatus (such as described below) and then causes the prosthetic valveto expand to its functional size inside the patient's body when deployedfrom the delivery apparatus. If the prosthetic valve is aballoon-expandable prosthetic valve that is adapted to be crimped ontoan inflatable balloon of a delivery apparatus and expanded to itsfunctional size by inflation of the balloon, the stent 12 can be made ofa suitable ductile material, such as stainless steel.

The stent 12 has an inflow end 26 and an outflow end 27. The meshstructure formed by struts 16 comprises a generally cylindrical “upper”or outflow end portion 20, an outwardly bowed or distended intermediatesection 22, and an inwardly bowed “lower” or inflow end portion 24. Theintermediate section 22 desirably is sized and shaped to extend into theValsalva sinuses in the root of the aorta to assist in anchoring theprosthetic valve in place once implanted. As shown, the mesh structuredesirably has a curved shape along its entire length that graduallyincreases in diameter from the outflow end portion 20 to theintermediate section 22, then gradually decreases in diameter from theintermediate section 22 to a location on the inflow end portion 24, andthen gradually increases in diameter to form a flared portionterminating at the inflow end 26.

When the prosthetic valve is in its expanded state, the intermediatesection 22 has a diameter D₁, the inflow end portion 24 has a minimumdiameter D₂, the inflow end 26 has a diameter D₃, and the outflow endportion 20 has a diameter D₄, where D₂ is less than D₁ and D₃, and D₄ isless than D₂. In addition, D₁ and D₃ desirably are greater than thediameter of the native annulus in which the prosthetic valve is to beimplanted. In this manner, the overall shape of the stent 12 assists inretaining the prosthetic valve at the implantation site. Morespecifically, and referring to FIGS. 5A and 5B, the prosthetic valve 10can be implanted within a native valve (the aortic valve in theillustrated example) such that the lower section 24 is positioned withinthe aortic annulus 28, the intermediate section 24 extends above theaortic annulus into the Valsalva's sinuses 56, and the lower flared end26 extends below the aortic annulus. The prosthetic valve 10 is retainedwithin the native valve by the radial outward force of the lower section24 against the surrounding tissue of the aortic annulus 28 as well asthe geometry of the stent. Specifically, the intermediate section 24 andthe flared lower end 26 extend radially outwardly beyond the aorticannulus 28 to better resist against axial dislodgement of the prostheticvalve in the upstream and downstream directions (toward and away fromthe aorta). Depending on the condition of the native leaflets 58, theprosthetic valve typically is deployed within the native annulus 28 withthe native leaflets 58 folded upwardly and compressed between the outersurface of the stent 12 and the walls of the Valsalva sinuses, asdepicted in FIG. 5B. In some cases, it may be desirable to excise theleaflets 58 prior to implanting the prosthetic valve 10.

Known prosthetic valves having a self-expanding frame typically haveadditional anchoring devices or frame portions that extend into andbecome fixed to non-diseased areas of the vasculature. Because the shapeof the stent 12 assists in retaining the prosthetic valve, additionalanchoring devices are not required and the overall length L of the stentcan be minimized to prevent the stent upper portion 20 from extendinginto the non-diseased area of the aorta, or to at least minimize theextent to which the upper portion 20 extends into the non-diseased areaof the aorta. Avoiding the non-diseased area of the patient'svasculature helps avoid complications if future intervention isrequired. For example, the prosthetic valve can be more easily removedfrom the patient because the stent is primarily anchored to the diseasedpart of the native valve. Furthermore, a shorter prosthetic valve ismore easily navigated around the aortic arch.

In particular embodiments, for a prosthetic valve intended for use in a22-mm to 24-mm annulus, the diameter D1 is about 28 mm to about 32 mm,with 30 mm being a specific example; the diameter D2 is about 24 mm toabout 28 mm, with 26 mm being a specific example; the diameter D3 isabout 28 mm to about 32 mm, with 30 mm being a specific example; and thediameter D4 is about 24 mm to about 28 mm, with 26 mm being a specificexample. The length L in particular embodiments is about 20 mm to about24 mm, with 22 mm being a specific example.

Referring to FIG. 1, the stent 12 can have a plurality of angularlyspaced retaining arms, or projections, in the form of posts 30 (three inthe illustrated embodiment) that extend from the stent upper portion 20.Each retaining arm 30 has a respective aperture 32 that is sized toreceive prongs of a valve-retaining mechanism that can be used to form areleasable connection between the prosthetic valve and a deliveryapparatus (described below). In alternative embodiments, the retainingarms 30 need not be provided if a valve-retaining mechanism is not used.

As best shown in FIGS. 6 and 7, the leaflet assembly 14 in theillustrated embodiment comprises three leaflets 34 a, 34 b, 34 c made ofa flexible material. Each leaflet has an inflow end portion 60 and anoutflow end portion 62. The leaflets can comprise any suitablebiological material (e.g., pericardial tissue, such as bovine or equinepericadium), bio-compatible synthetic materials, or other suchmaterials, such as those described in U.S. Pat. No. 6,730,118, which isincorporated herein by reference. The leaflet assembly 14 can include anannular reinforcing skirt 42 that is secured to the outer surfaces ofthe inflow end portions of the leaflets 34 a, 34 b, 34 c at a sutureline 44 adjacent the inflow end of the prosthetic valve. The inflow endportion of the leaflet assembly 14 can be secured to the stent 12 bysuturing the skirt 42 to struts 16 of the lower section 24 of the stent(best shown in FIG. 1). As shown in FIG. 7, the leaflet assembly 14 canfurther include an inner reinforcing strip 46 that is secured to theinner surfaces of the inflow end portions 60 of the leaflets.

Referring to FIGS. 1 and 2, the outflow end portion of the leafletassembly 14 can be secured to the upper portion of the stent 12 at threeangularly spaced commissure attachments of the leaflets 34 a, 34 b, 34c. As best shown in FIG. 2, each commissure attachment can be formed bywrapping a reinforcing section 36 around adjacent upper edge portions 38of a pair of leaflets at the commissure formed by the two leaflets andsecuring the reinforcing section 36 to the edge portions 38 with sutures48. The sandwiched layers of the reinforcing material and leaflets canthen be secured to the struts 16 of the stent 12 with sutures 50adjacent the outflow end of the stent. The leaflets therefore desirablyextend the entire length or substantially the entire length of the stentfrom the inflow end 26 to the outflow end 27. The reinforcing sections36 reinforces the attachment of the leaflets to the stent so as tominimize stress concentrations at the suture lines and avoid “needleholes” on the portions of the leaflets that flex during use. Thereinforcing sections 36, the skirt 42, and the inner reinforcing strip46 desirably are made of a bio-compatible synthetic material, such aspolytetrafluoroethylene (PTFE), or a woven fabric material, such aswoven polyester (e.g., polyethylene terephtalate) (PET)).

FIG. 7 shows the operation of the prosthetic valve 10. During diastole,the leaflets 34 a, 34 b, 34 c collapse to effectively close theprosthetic valve. As shown, the curved shape of the intermediate section22 of the stent 12 defines a space between the intermediate section andthe leaflets that mimics the Valsalva sinuses. Thus, when the leafletsclose, backflow entering the “sinuses” creates a turbulent flow of bloodalong the upper surfaces of the leaflets, as indicated by arrows 52.This turbulence assists in washing the leaflets and the skirt 42 tominimize clot formation.

The prosthetic valve 10 can be implanted in a retrograde approach wherethe prosthetic valve, mounted in a crimped state at the distal end of adelivery apparatus, is introduced into the body via the femoral arteryand advanced through the aortic arch to the heart, as further describedin U.S. Patent Publication No. 2008/0065011, which is incorporatedherein by reference.

FIGS. 8 and 9 show a delivery apparatus 100, according to oneembodiment, that can be used to deliver a self-expanding prostheticvalve, such as prosthetic valve 10 described above, through a patient'svasculature. The delivery apparatus 100 comprises a first, outermost ormain catheter 102 (shown alone in FIG. 10) having an elongated shaft104, the distal end of which is coupled to a delivery sheath 106 (FIG.18; also referred to as a delivery cylinder). The proximal end of themain catheter 102 is connected to a handle of the delivery apparatus.FIGS. 23-26 show an embodiment of a handle mechanism having an electricmotor for operating the delivery apparatus. The handle mechanism isdescribed in detail below. During delivery of a prosthetic valve, thehandle can be used by a surgeon to advance and retract the deliveryapparatus through the patient's vasculature. Although not required, themain catheter 102 can comprise a guide catheter that is configured toallow a surgeon to guide or control the amount the bending or flexing ofa distal portion of the shaft 104 as it is advanced through thepatient's vasculature, such as further described below. Anotherembodiment of a guide catheter is disclosed in U.S. Patent PublicationNo. 2008/0065011, which is incorporated herein by reference.

As best shown in FIG. 9, the delivery apparatus 100 also includes asecond, intermediate catheter 108 (also referred to herein as a torqueshaft catheter) having an elongated shaft 110 (also referred to hereinas a torque shaft) and an elongated screw 112 connected to the distalend of the shaft 110. The shaft 110 of the intermediate catheter 108extends coaxially through the shaft 104 of the main catheter 102. Thedelivery apparatus 100 can also include a third, nose-cone catheter 118having an elongated shaft 120 and a nose piece, or nose cone, 122secured to the distal end portion of the shaft 120. The nose piece 122can have a tapered outer surface as shown for atraumatic trackingthrough the patient's vasculature. The shaft 120 of the nose-conecatheter extends through the prosthetic valve 10 (not shown in FIGS.8-9) and the shaft 110 of the intermediate catheter 108. In theillustrated configuration, the innermost shaft 120 is configured to bemoveable axially and rotatably relative to the shafts 104, 110, and thetorque shaft 110 is configured to be rotatable relative to the shafts104, 120 to effect valve deployment and release of the prosthetic valvefrom the delivery apparatus, as described in detail below. Additionally,the innermost shaft 120 can have a lumen for receiving a guide wire sothat the delivery apparatus can be advanced over the guide wire insidethe patient's vasculature.

As best shown in FIG. 10, the outer catheter 102 can comprise a flexcontrol mechanism 168 at a proximal end thereof to control the amountthe bending or flexing of a distal portion of the outer shaft 104 as itis advanced through the patient's vasculature, such as further describedbelow. The outer shaft 104 can comprise a proximal segment 166 thatextends from the flex control mechanism 168 and a distal segment 126that comprises a slotted metal tube that increases the flexibility ofthe outer shaft at this location. The distal end portion of the distalsegment 126 can comprises an outer fork 130 of a valve-retainingmechanism 114 that is configured to releasably secure a prosthetic valve10 to the delivery apparatus 100 during valve delivery, as described indetail below.

FIG. 28A is an enlarged view of a portion of the distal segment 126 ofthe outer shaft 104. FIG. 28B shows the cut pattern that can be used toform the distal segment 126 by laser cutting the pattern in a metaltube. The distal segment 126 comprises a plurality of interconnectedcircular bands or links 160 forming a slotted metal tube. A pull wire162 can be positioned inside the distal segment 126 and can extend froma location 164 of the distal segment 126 (FIGS. 10 and 12) to the flexcontrol mechanism. The distal end of the pull wire 162 can be secured tothe inner surface of the distal segment 126 at location 164, such as bywelding. The proximal end of the pull wire 162 can be operativelyconnected to the flex control mechanism 168, which is configured toapply and release tension to the pull wire in order to control bendingof the shaft, as further described below. The links 160 of the shaft andthe gaps between adjacent links are shaped to allow bending of the shaftupon application of light pulling force on the pull wire 162. In theillustrated embodiment, as best shown in FIG. 12, the distal segment 126is secured to a proximal segment 166 having a different construction(e.g., one or more layers of polymeric tubing). In the illustratedembodiment, the proximal segment 166 extends from the flex controlmechanism 168 to the distal segment 126 and therefore makes up themajority of the length of the outer shaft 104. In alternativeembodiments, the entire length or substantially the entire length of theouter shaft 104 can be formed from a slotted metal tube comprising oneor more sections of interconnected links 160. In any case, the use of amain shaft having such a construction can allow the delivery apparatusto be highly steerable, especially when use in combination with a torqueshaft having the construction shown in FIGS. 40 and 41 (describedbelow).

The width of the links 160 can be varied to vary the flexibility of thedistal segment along its length. For example, the links within thedistal end portion of the slotted tube can be relatively narrower toincrease the flexibility of the shaft at that location while the linkswithin the proximal end portion of the slotted tube can be relativelywider so that the shaft is relatively less flexible at that location.

FIG. 29A shows an alternative embodiment of a distal segment, indicatedat 126′, which can be formed, for example, by laser cutting a metaltube. The segment 126′ can comprise the distal segment of an outer shaftof a delivery apparatus (as shown in FIG. 12) or substantially theentire length of an outer shaft can have the construction shown in FIG.29A. FIG. 29B shows the cut pattern for forming the segment 126′. Inanother embodiment, a delivery apparatus can include a composite outershaft comprising a laser-cut metal tube laminated with a polymeric outerlayer that is fused within the gaps in the metal layer. In one example,a composite shaft can comprise a laser cut metal tube having the cutpattern of FIGS. 29A and 29B and a polymeric outer layer fused in thegaps between the links 160 of the metal tube. In another example, acomposite shaft can comprise a laser cut metal tube having the cutpattern of FIGS. 28A and 28B and a polymeric outer layer fused in thegaps between the links 160 of the metal tube. A composite shaft also caninclude a polymeric inner layer fused in the gaps between the links 160of the metal tube.

Referring to FIGS. 8A and 11, the flex control mechanism 168 cancomprise a rotatable housing, or handle portion, 186 that houses a slidenut 188 mounted on a rail 192. The slide nut 188 is prevented fromrotating within the housing by one or more rods 192, each of which ispartially disposed in a corresponding recess within the rail 192 and aslot or recess on the inside of the nut 188. The proximal end of thepull wire 162 is secured to the nut 188. The nut 188 has externalthreads that engage internal threads of the housing. Thus, rotating thehousing 186 causes the nut 188 to move axially within the housing in theproximal or distal direction, depending on the direction of rotation ofthe housing. Rotating the housing in a first direction (e.g.,clockwise), causes the nut to travel in the proximal direction, whichapplies tension to the pull wire 162, which causes the distal end of thedelivery apparatus to bend or flex. Rotating the housing in a seconddirection (e.g., counterclockwise), causes the nut to travel in thedistal direction, which relieves tension in the pull wire 162 and allowsthe distal end of the delivery apparatus to flex back to its pre-flexedconfiguration under its own resiliency.

As best shown in FIG. 13, the torque shaft catheter 108 includes anannular projection in the form of a ring 128 (also referred to as ananchoring disc) mounted on the distal end portion of the torque shaft110 adjacent the screw 112. The ring 128 is secured to the outer surfaceof the torque shaft 110 such that it cannot move axially or rotationallyrelative to the torque shaft. The inner surface of the outer shaft 104is formed with a feature, such as a slot or recess, that receives thering 128 in such a manner that the ring and the corresponding feature onthe inner surface of the outer shaft 104 allow the torque shaft 110 torotate relative to the outer shaft 104 but prevent the torque shaft frommoving axially relative to the outer shaft. The corresponding feature onthe outer shaft 104 that receives the ring 128 can be inwardly extendingtab portions formed in the distal segment 126, such as shown at 164 inFIG. 12. In the illustrated embodiment (as best shown in FIG. 14), thering 128 is an integral part of the screw 112 (i.e., the screw 112 andthe ring 128 are portions of single component). Alternatively, the screw112 and the ring are separately formed components but are both fixedlysecured to the distal end of the torque shaft 110.

The torque shaft 110 desirably is configured to be rotatable relative tothe delivery sheath 106 to effect incremental and controlled advancementof the prosthetic valve 10 from the delivery sheath 106. To such ends,and according to one embodiment, the delivery apparatus 100 can includea sheath retaining ring in the form of a threaded nut 150 mounted on theexternal threads of the screw 112. As best shown in FIG. 16, the nut 150includes internal threads 152 that engage the external threads of thescrew and axially extending legs 154. Each leg 154 has a raised distalend portion that extends into and/or forms a snap fit connection withopenings 172 in the proximal end of the sheath 106 (as best shown inFIG. 18) so as to secure the sheath 106 to the nut 150. As illustratedin FIGS. 17B and 18, the sheath 106 extends over the prosthetic valve 10and retains the prosthetic valve in a radially compressed state untilthe sheath 106 is retracted by the user to deploy the prosthetic valve.

As best shown in FIGS. 21 and 22, the outer fork 130 of thevalve-retaining mechanism comprises a plurality of prongs 134, each ofwhich extends through a region defined between two adjacent legs 154 ofthe nut so as to prevent rotation of the nut relative to the screw 112upon rotation of the screw. As such, rotation of the torque shaft 110(and thus the screw 112) causes corresponding axial movement of the nut150. The connection between the nut 150 and the sheath 106 is configuredsuch that axially movement of the nut along the screw 112 (in the distalor proximal direction) causes the sheath 106 to move axially in the samedirection relative to the screw and the valve-retaining mechanism. FIG.21 shows the nut 150 in a distal position wherein the sheath 106 (notshown in FIG. 21) extends over and retains the prosthetic valve 10 in acompressed state for delivery. Movement of the nut 150 from the distalposition (FIG. 21) to a proximal position (FIG. 22) causes the sheath106 to move in the proximal direction, thereby deploying the prostheticvalve from the sheath 106. Rotation of the torque shaft 110 to effectaxial movement of the sheath 106 can be accomplished with a motorizedmechanism (such as shown in FIGS. 23-26 and described below) or bymanually turning a crank or wheel (such as shown in the embodiment ofFIGS. 30-37, described below).

FIG. 17 shows an enlarged view of the nose cone 122 secured to thedistal end of the innermost shaft 120. The nose cone 122 in theillustrated embodiment includes a proximal end portion 174 that is sizedto fit inside the distal end of the sheath 106. An intermediate section176 of the nose cone is positioned immediately adjacent the end of thesheath in use and is formed with a plurality of longitudinal grooves, orrecessed portions, 178. The diameter of the intermediate section 176 atits proximal end 180 desirably is slightly larger than the outerdiameter of the sheath 106. The proximal end 180 can be held in closecontact with the distal end of the sheath 106 to protect surroundingtissue from coming into contact with the metal edge of the sheath. Thegrooves 178 allow the intermediate section to be compressed radially asthe delivery apparatus is advanced through an introducer sheath. Thisallows the nose cone to be slightly oversized relative to the innerdiameter of the introducer sheath. FIG. 17B shows a cross-section thenose cone 122 and the sheath 106 in a delivery position with theprosthetic valve retained in a compressed delivery state inside thesheath 106 (for purposes of illustration, only the stent 12 of theprosthetic valve is shown). As shown, the proximal end 180 of theintermediate section 176 can abut the distal end of the sheath 106 and atapered proximal surface 182 of the nose cone can extend within a distalportion of the stent 12.

As noted above, the delivery apparatus 100 can include a valve-retainingmechanism 114 (FIG. 8B) for releasably retaining a stent 12 of aprosthetic valve. The valve-retaining mechanism 114 can include a firstvalve-securement component in the form of an outer fork 130 (as bestshown in FIG. 12) (also referred to as an “outer trident” or “releasetrident”), and a second valve-securement component in the form of aninner fork 132 (as best shown in FIG. 17) (also referred to as an “innertrident” or “locking trident”). The outer fork 130 cooperates with theinner fork 132 to form a releasably connection with the retaining arms30 of the stent 12.

The proximal end of the outer fork 130 is connected to the distalsegment 126 of the outer shaft 104 and the distal end of the outer forkis releasably connected to the stent 12. In the illustrated embodiment,the outer fork 130 and the distal segment 126 can be integrally formedas a single component (e.g., the outer fork and the distal segment canbe laser cut or otherwise machined from a single piece of metal tubing),although these components can be separately formed and subsequentlyconnected to each other. The inner fork 132 can be mounted on the nosecatheter shaft 120 (as best shown in FIG. 17). The inner fork 132connects the stent to the distal end portion of the nose catheter shaft120. The nose catheter shaft 120 can be moved axially relative to theouter shaft 104 to release the prosthetic valve from the valve-retainingmechanism, as further described below.

As best shown in FIG. 12, the outer fork 130 includes a plurality ofangularly-spaced prongs 134 (three in the illustrated embodiment)corresponding to the retaining arms 30 of the stent 12, which prongsextend from the distal end of distal segment 126. The distal end portionof each prong 134 includes a respective opening 140. As best shown inFIG. 17, the inner fork 132 includes a plurality of angularly-spacedprongs 136 (three in the illustrated embodiment) corresponding to theretaining arms 30 of the stent 12, which prongs extend from a baseportion 138 at the proximal end of the inner fork. The base portion 138of the inner fork is fixedly secured to the nose catheter shaft 120(e.g., with a suitable adhesive) to prevent axial and rotationalmovement of the inner fork relative to the nose catheter shaft 120.

Each prong of the outer fork cooperates with a corresponding prong ofthe inner fork to form a releasable connection with a retaining arm 30of the stent. In the illustrated embodiment, for example, the distal endportion of each prong 134 is formed with an opening 140. When theprosthetic valve is secured to the delivery apparatus (as best shown inFIG. 19), each retaining arm 30 of the stent 12 extends inwardly throughan opening 140 of a prong 134 of the outer fork and a prong 136 of theinner fork is inserted through the opening 32 of the retaining arm 30 soas to retain the retaining arm 30 from backing out of the opening 140.FIG. 42 also shows the prosthetic valve 10 secured to the deliveryapparatus by the inner and outer forks before the prosthetic valve isloaded into the sheath 106. Retracting the inner prongs 136 proximally(in the direction of arrow 184 in FIG. 20) to remove the prongs from theopenings 32 is effective to release the prosthetic valve 10 from theretaining mechanism. When the inner fork 132 is moved to a proximalposition (FIG. 20), the retaining arms 30 of the stent can move radiallyoutwardly from the openings 140 in the outer fork 130 under theresiliency of the stent. In this manner, the valve-retaining mechanism114 forms a releasable connection with the prosthetic valve that issecure enough to retain the prosthetic valve relative to the deliveryapparatus to allow the user to fine tune or adjust the position of theprosthetic valve after it is deployed from the delivery sheath. When theprosthetic valve is positioned at the desired implantation site, theconnection between the prosthetic valve and the retaining mechanism canbe released by retracting the nose catheter shaft 120 relative to theouter shaft 104 (which retracts the inner fork 132 relative to the outerfork 130).

Techniques for compressing and loading the prosthetic valve 10 into thesheath 106 are described below. Once the prosthetic valve 10 is loadedin the delivery sheath 106, the delivery apparatus 100 can be insertedinto the patient's body for delivery of the prosthetic valve. In oneapproach, the prosthetic valve can be delivered in a retrogradeprocedure where delivery apparatus is inserted into a femoral artery andadvanced through the patient's vasculature to the heart. Prior toinsertion of the delivery apparatus, an introducer sheath can beinserted into the femoral artery followed by a guide wire, which isadvanced through the patient's vasculature through the aorta and intothe left ventricle. The delivery apparatus 100 can then be insertedthrough the introducer sheath and advanced over the guide wire until thedistal end portion of the delivery apparatus containing the prostheticvalve 10 is advanced to a location adjacent to or within the nativeaortic valve.

Thereafter, the prosthetic valve 10 can be deployed from the deliveryapparatus 100 by rotating the torque shaft 110 relative to the outershaft 104. As described below, the proximal end of the torque shaft 110can be operatively connected to a manually rotatable handle portion or amotorized mechanism that allows the surgeon to effect rotation of thetorque shaft 110 relative to the outer shaft 104. Rotation of the torqueshaft 110 and the screw 112 causes the nut 150 and the sheath 106 tomove in the proximal direction toward the outer shaft (FIG. 22), whichdeploys the prosthetic valve from the sheath. Rotation of the torqueshaft 110 causes the sheath to move relative to the prosthetic valve ina precise and controlled manner as the prosthetic valve advances fromthe open distal end of the delivery sheath and begins to expand. Hence,unlike known delivery apparatus, as the prosthetic valve begins toadvance from the delivery sheath and expand, the prosthetic valve isheld against uncontrolled movement from the sheath caused by theexpansion force of the prosthetic valve against the distal end of thesheath. In addition, as the sheath 106 is retracted, the prostheticvalve 10 is retained in a stationary position relative to the ends ofthe inner shaft 120 and the outer shaft 104 by virtue of thevalve-retaining mechanism 114. As such, the prosthetic valve 10 can beheld stationary relative to the target location in the body as thesheath is retracted. Moreover, after the prosthetic valve is partiallyadvanced from the sheath, it may be desirable to retract the prostheticvalve back into the sheath, for example, to reposition the prostheticvalve or to withdraw the prosthetic valve entirely from the body. Thepartially deployed prosthetic valve can be retracted back into thesheath by reversing the rotation of the torque shaft, which causes thesheath 106 to advance back over the prosthetic valve in the distaldirection.

In known delivery devices, the surgeon must apply push-pull forces tothe shaft and/or the sheath to unsheathe the prosthetic valve. It istherefore difficult to transmit forces to the distal end of the devicewithout distorting the shaft (e.g., compressing or stretching the shaftaxially), which in turn causes uncontrolled movement of the prostheticvalve during the unsheathing process. To mitigate this effect, the shaftand/or sheath can be made more rigid, which is undesirable because thedevice becomes harder to steer through the vasculature. In contrast, themanner of unsheathing the prosthetic valve described above eliminatesthe application of push-pull forces on the shaft, as required in knowndevices, so that relatively high and accurate forces can be applied tothe distal end of the shaft without compromising the flexibility of thedevice. In certain embodiments, as much as 20 lbs. of force can betransmitted to the end of the torque shaft without adversely affectingthe unsheathing process. In contrast, prior art devices utilizingpush-pull mechanisms typically cannot exceed about 5 lbs. of forceduring the unsheathing process.

After the prosthetic valve 10 is advanced from the delivery sheath andexpands to its functional size (the expanded prosthetic valve 10 securedto the delivery apparatus is depicted in FIG. 42), the prosthetic valveremains connected to the delivery apparatus via the retaining mechanism114. Consequently, after the prosthetic valve is advanced from thedelivery sheath, the surgeon can reposition the prosthetic valverelative to the desired implantation position in the native valve suchas by moving the delivery apparatus in the proximal and distaldirections or side to side, or rotating the delivery apparatus, whichcauses corresponding movement of the prosthetic valve. The retainingmechanism 114 desirably provides a connection between the prostheticvalve and the delivery apparatus that is secure and rigid enough toretain the position of the prosthetic valve relative to the deliveryapparatus against the flow of the blood as the position of theprosthetic valve is adjusted relative to the desired implantationposition in the native valve. Once the surgeon positions the prostheticvalve at the desired implantation position in the native valve, theconnection between the prosthetic valve and the delivery apparatus canbe released by retracting the innermost shaft 120 in the proximaldirection relative to the outer shaft 104, which is effective to retractthe inner fork 132 to withdraw its prongs 136 from the openings 32 inthe retaining arms 30 of the prosthetic valve (FIG. 20). Slightlyretracting of the outer shaft 104 allows the outer fork 130 to back offthe retaining arms 30 of the prosthetic valve, which slide outwardlythrough openings 140 in the outer fork to completely disconnect theprosthetic valve from the retaining mechanism 114. Thereafter, thedelivery apparatus can be withdrawn from the body, leaving theprosthetic aortic valve 10 implanted within the native valve (such asshown in FIGS. 5A and 5B).

The delivery apparatus 100 has at its distal end a semi-rigid segmentcomprised of relatively rigid components used to transform rotation ofthe torque shaft into axial movement of the sheath. In particular, thissemi-rigid segment in the illustrated embodiment is comprised of theprosthetic valve and the screw 112. An advantage of the deliveryapparatus 100 is that the overall length of the semi-rigid segment isminimized because the nut 150 is used rather than internal threads onthe outer shaft to affect translation of the sheath. The reduced lengthof the semi-rigid segment increases the overall flexibility along thedistal end portion of the delivery catheter. Moreover, the length andlocation of the semi-rigid segment remains constant because the torqueshaft does not translate axially relative to the outer shaft. As such,the curved shape of the delivery catheter can be maintained during valvedeployment, which improves the stability of the deployment. A furtherbenefit of the delivery apparatus 100 is that the ring 128 prevents thetransfer of axial loads (compression and tension) to the section of thetorque shaft 110 that is distal to the ring.

In an alternative embodiment, the delivery apparatus can be adapted todeliver a balloon-expandable prosthetic valve. As described above, thevalve retaining mechanism 114 can be used to secure the prosthetic valveto the end of the delivery apparatus. Since the stent of the prostheticvalve is not self-expanding, the sheath 106 can be optional. Theretaining mechanism 114 enhances the pushability of the deliveryapparatus and prosthetic valve assembly through an introducer sheath.

FIGS. 23-26 illustrate the proximal end portion of the deliveryapparatus 100, according to one embodiment. The delivery apparatus 100can comprise a handle 202 that is configured to be releasablyconnectable to the proximal end portion of a catheter assembly 204comprising catheters 102, 108, 118. It may be desirable to disconnectthe handle 202 from the catheter assembly 204 for various reasons. Forexample, disconnecting the handle can allow another device to be slidover the catheter assembly, such as a valve-retrieval device or a deviceto assist in steering the catheter assembly. It should be noted that anyof the features of the handle 202 and the catheter assembly 204 can beimplemented in any of the embodiments of the delivery apparatusesdisclosed herein.

FIGS. 23 and 24 show the proximal end portion of the catheter assembly204 partially inserted into a distal opening of the handle 202. Theproximal end portion of the main shaft 104 is formed with an annulargroove 212 (as best shown in FIG. 24) that cooperates with a holdingmechanism, or latch mechanism, 214 inside the handle. When the proximalend portion of the catheter assembly is fully inserted into the handle,as shown in FIGS. 25 and 26, an engaging portion 216 of the holdingmechanism 214 extends at least partially into the groove 212. One sideof the holding mechanism 214 is connected to a button 218 that extendsthrough the housing of the handle. The opposite side of the holdingmechanism 214 is contacted by a spring 220 that biases the holdingmechanism to a position engaging the main shaft 104 at the groove 212.The engagement of the holding mechanism 214 within the groove 212prevents axial separation of the catheter assembly from the handle. Thecatheter assembly can be released from the handle by depressing button218, which moves the holding mechanism 214 from locking engagement withthe main shaft. Furthermore, the main shaft 104 can be formed with aflat surface portion within the groove 212. The flat surface portion ispositioned against a corresponding flat surface portion of the engagingportion 216. This engagement holds the main shaft 104 stationaryrelative to the torque shaft 110 as the torque shaft is rotated duringvalve deployment.

The proximal end portion of the torque shaft 110 can have a driven nut222 (FIG. 26) that is slidably received in a drive cylinder 224 (FIG.25) mounted inside the handle. The nut 222 can be secured to theproximal end of the torque shaft 100 by securing the nut 222 over acoupling member 170 (FIG. 15). FIG. 26 is a perspective view of theinside of the handle 202 with the drive cylinder and other componentsremoved to show the driven nut and other components positioned withinthe drive cylinder. The cylinder 224 has a through opening (or lumen)extending the length of the cylinder that is shaped to correspond to theflats of the nut 222 such that rotation of the drive cylinder iseffective to rotate the nut 222 and the torque shaft 110. The drivecylinder can have an enlarged distal end portion 236 that can house oneor more seals (e.g., o-rings 246) that form a seal with the outersurface of the main shaft 104 (FIG. 25). The handle can also house afitting 238 that has a flush port in communication with the lumen of thetorque shaft and/or the lumen of the main shaft.

The drive cylinder 224 is operatively connected to an electric motor 226through gears 228 and 230. The handle can also house a batterycompartment 232 that contains batteries for powering the motor 226.Rotation of the motor in one direction causes the torque shaft 110 torotate, which in turn causes the sheath 106 to retract and uncover aprosthetic valve at the distal end of the catheter assembly. Rotation ofthe motor in the opposite direction causes the torque shaft to rotate inan opposite direction, which causes the sheath to move back over theprosthetic valve. An operator button 234 on the handle allows a user toactivate the motor, which can be rotated in either direction toun-sheath a prosthetic valve or retrieve an expanded or partiallyexpanded prosthetic valve.

As described above, the distal end portion of the nose catheter shaft120 can be secured to an inner fork 132 that is moved relative to anouter fork 130 to release a prosthetic valve secured to the end of thedelivery apparatus. Movement of the shaft 120 relative to the main shaft104 (which secures the outer fork 130) can be effected by a proximal endportion 240 of the handle that is slidable relative to the main housing244. The end portion 240 is operatively connected to the shaft 120 suchthat movement of the end portion 240 is effective to translate the shaft120 axially relative to the main shaft 104 (causing a prosthetic valveto be released from the inner and outer forks). The end portion 240 canhave flexible side panels 242 on opposite sides of the handle that arenormally biased outwardly in a locked position to retain the end portionrelative to the main housing 244. During deployment of the prostheticvalve, the user can depress the side panels 242, which disengage fromcorresponding features in the housing and allow the end portion 240 tobe pulled proximally relative to the main housing, which causescorresponding axial movement of the shaft 120 relative to the mainshaft. Proximal movement of the shaft 120 causes the prongs 136 of theinner fork 132 to disengage from the apertures 32 in the stent 12, whichin turn allows the retaining arms 30 of the stent to deflect radiallyoutwardly from the openings 140 in the prongs 134 of the outer fork 130,thereby releasing the prosthetic valve.

FIG. 27 shows an alternative embodiment of a motor, indicated at 400,that can be used to drive a torque shaft (e.g., torque shaft 110). Inthis embodiment, a catheter assembly can be connected directly to oneend of a shaft 402 of the motor, without gearing. The shaft 402 includesa lumen that allows for passage of an innermost shaft (e.g., shaft 120)of the catheter assembly, a guide wire, and/or fluids for flushing thelumens of the catheter assembly.

Alternatively, the power source for rotating the torque shaft 110 can bea hydraulic power source (e.g., hydraulic pump) or pneumatic(air-operated) power source that is configured to rotate the torqueshaft. In another embodiment, the handle can have a manually movablelever or wheel that is operable to rotate the torque shaft 110.

In another embodiment, a power source (e.g., an electric, hydraulic, orpneumatic power source) can be operatively connected to a shaft, whichis turn is connected to a prosthetic valve 10. The power source isconfigured to reciprocate the shaft longitudinally in the distaldirection relative to a valve sheath in a precise and controlled mannerin order to advance the prosthetic valve from the sheath. Alternatively,the power source can be operatively connected to the sheath in order toreciprocate the sheath longitudinally in the proximal direction relativeto the prosthetic valve to deploy the prosthetic valve from the sheath.

FIGS. 30-37 illustrate a delivery apparatus 300, according to anotherembodiment. FIGS. 30-33 show the distal end portion of the deliveryapparatus 300. FIGS. 34-35 show the proximal end portion of the deliveryapparatus 300. FIGS. 36-37 show the deployment of a prosthetic valve 10from the delivery apparatus 300 (the leaflets of the prosthetic valveare removed for clarify in the figures).

The delivery apparatus 300 comprises a first, outer catheter 302 havingan elongated shaft 304 extending between a valve retaining mechanism 306at the distal end of the apparatus (FIGS. 32 and 33) and a handleportion 308 at the proximal end of the apparatus (FIGS. 34 and 35). Thedistal end of the main catheter shaft 304 is coupled to thevalve-retaining mechanism 306, which in turn is secured to theprosthetic valve 10. The outer catheter 302 can be a guide catheter thatis configured to permit selective bending or flexing of a portion of theshaft 304 to facilitate advancement of the delivery apparatus throughthe patient's vasculature.

The delivery apparatus also includes a second, torque catheter 310having an elongated torque shaft 312 that extends through the maincatheter shaft 304. The distal end of the torque shaft 304 is connectedto a flexible screw mechanism 314 comprising a flexible shaft 316extending through the retaining mechanism 306 and one or more screwmembers 318 spaced along the length of the shaft 316 (FIGS. 32 and 33).As shown in FIG. 33, the shaft 316 of the screw mechanism 314 exhibitssufficient flexibility to permit bending or flexing to assist intracking the delivery apparatus through the patient's vasculature. Themain catheter shaft 304 can be formed with internal threads that engagethe external threads of the screw members 318. For example, a distal endportion of the main shaft 304 (e.g., an 11-mm segment at the distal endof the shaft 304) can be formed with internal threads. The proximal endportion of the torque shaft 312 extends into the handle portion 308where it is coupled to a control knob 320 to permit rotation of thetorque shaft relative to the main catheter shaft 304 (FIGS. 34 and 35),as further described below.

In operation, each screw member 318 passes through and engages theinternally threaded portion of the main shaft 304. The screw members 318desirably are spaced from each other such that a screw member 318 canengage one end of the internally threaded portion of the main shaft 304before an adjacent screw member 318 disengages from the other end of theinternally threaded portion of the main shaft as the screw members passthrough the internally threaded portion so as to prevent or at leastminimize application of axially directed forces on the torque shaft. Inthis manner, relatively high unsheathing forces can be applied to thesheath without compromising the overall flexibility of the deliveryapparatus.

The delivery apparatus can also include a third, nose catheter 324having an elongated shaft 326 that is connected at its distal end to anose piece 328. The nose catheter shaft 326 extends through the torqueshaft 312 and has a proximal end portion that extends outwardly from theproximal end of the handle portion 308 (FIGS. 34 and 35). The maincatheter shaft 304, the torque shaft 312, and the nose catheter shaft326 desirably are configured to be moveable axially relative to eachother.

As shown in FIGS. 30 and 31, the delivery apparatus can further includea movable sheath 322 that extends over the compressed prosthetic valve10. The sheath 322 is connected to screw mechanism 314 so thatlongitudinal movement of the torque shaft 312 and the screw mechanism314 causes corresponding longitudinal movement of the sheath 322. Forexample, the sheath can have inwardly extending prongs 358 (FIG. 31)extending into respective apertures 360 of fingers 362 (FIG. 32), whichin turn are connected to the distal end of the flexible shaft 316.Fingers 362 desirably are connected to the shaft 316 by a swivel jointthat pushes or pulls fingers 362 when the shaft 316 moves distally orproximally, respective, yet allows the shaft 316 to rotate relative tothe fingers 362. Consequently, rotation of the torque shaft 312 and thescrew mechanism 314 relative to the main shaft 304 is effective to causethe sheath 322 to move in the proximal and distal directions (asindicated by double-headed arrow 330 in FIG. 30) relative to theprosthetic valve to permit controlled deployment of the prosthetic valvefrom the sheath, as further described below.

Referring to FIGS. 32 and 33, the valve-retaining mechanism 306comprises an outer fork 330 and an inner fork 332. A portion of thefinger 362 is cut away in FIG. 33 to show the inner fork 332. The outerfork 330 comprises a head portion 334 and a plurality of elongated,flexible prongs 336 (three in the illustrated embodiment) extending fromthe head portion 334. The head portion 334 can be formed with resilientretaining flanges 338 to permit the outer fork to form a snap-fitconnection with a stepped shaft portion of the main catheter shaft 304,as described above. The inner fork 332 has a head portion 340 that isfixedly secured to the nose catheter shaft 326 and a plurality ofelongated prongs 342 extending from the head portion 340. The distal endportions of the prongs 336 of the outer fork can be formed withapertures 344 sized to receive respective retaining arms 30 of theprosthetic valve 10. The distal ends of the prongs 342 of the inner fork332 extend through the apertures 32 in the retaining arms 30 to form areleasable connection for securing the prosthetic valve 10, similar tovalve-retaining mechanism 114 described above and shown in FIGS. 19-20.After the prosthetic valve is deployed form the sheath 322, theconnection between the prosthetic valve and the retaining mechanism 306can be released by retracting the nose catheter shaft 326 relative tothe main catheter shaft 304 to withdrawn the prongs 342 from theapertures 32 in the retaining arms 30. The outer prongs 336 and theshaft 316 of the screw mechanism 314 exhibit sufficient flexibility toallow that portion of the delivery apparatus to bend or flex as thedelivery apparatus is advanced through the patient's vasculature to theimplantation site, yet are rigid enough to permit repositioning of theprosthetic valve after it is deployed from the sheath 322. The outerfork 330, including prongs 336, can be made from any of various suitablematerials, such as metals (e.g., stainless steel) or polymers, thatprovide the desired flexibility.

Referring to FIGS. 34 and 35, the handle portion 308 comprises a housing346 that houses a first gear 348 and a second gear 350. The first gear348 has a shaft that extends through the housing and is connected to thecontrol knob 320 located on the outside of the housing. The second gear350 is disposed on and fixedly secured to the torque shaft 312. Thus,manual rotation of the control knob 320 causes rotation of the firstgear 348, which in turn rotates the second gear 350. The second gear 350rotates the torque shaft 312 and the screw mechanism 314 relative to themain catheter shaft 304, the valve-retaining mechanism 306, and theprosthetic valve 10. Rotation of the torque shaft 312 and the screwmechanism 314 in turn causes linear movement of the sheath 322 relativeto the prosthetic valve.

In use, the prosthetic valve 10 is loaded into the sheath 322 in aradially compressed state (as depicted in FIG. 30), which can beaccomplished, for example, by using one of the loading cones describedbelow. The delivery apparatus 300 is then inserted into the patient'svasculature and advanced to a position at or adjacent the implantationsite. The prosthetic valve 10 can then be deployed from the sheath byrotating the knob 320 on the handle portion, which in turn causes thetorque shaft 312 and the screw mechanism 316 to retract within the mainshaft 304, causing the sheath 322 to move in the proximal direction(arrow 352 in FIG. 31) to expose the prosthetic valve, as depicted inFIG. 31. Rotation of the knob 320 enables a controlled and preciseretraction of the sheath 322 during valve deployment. Advantageously,the sheath is retracted while the position of the prosthetic valve canbe held constant relative to the annulus at the implantation site duringthe unsheathing process. Rotation of the knob in the opposite directioncauses the sheath to move in the distal direction to again cover theprosthetic valve. Thus, after the prosthetic valve has been at leastpartially advanced from the sheath, it is possible to reverse rotationof the knob to bring the prosthetic valve back into the sheath in acompressed state if it becomes necessary to reposition the deliveryapparatus within the body or to completely withdraw the deliveryapparatus and the prosthetic valve from the body.

After the prosthetic valve 10 is advanced from the delivery sheath andexpands to its functional size (as shown in FIG. 36), the prostheticvalve remains connected to the delivery apparatus via the retainingmechanism 306. Consequently, after the prosthetic valve is advanced fromthe delivery sheath, the surgeon can reposition the prosthetic valverelative to the desired implantation position in the native valve suchas by moving the delivery apparatus in the proximal and distaldirections or side to side, or rotating the delivery apparatus, whichcauses corresponding movement of the prosthetic valve. The retainingmechanism 306 desirably provides a connection between the prostheticvalve and the delivery apparatus that is secure and rigid enough toretain the position of the prosthetic valve relative to the deliveryapparatus against the flow of the blood as the position of theprosthetic valve is adjusted relative to the desired implantationposition in the native valve. Once the surgeon positions the prostheticvalve at the desired implantation position in the native valve, thesurgeon can release the connection between the prosthetic valve and thedelivery apparatus by pulling the proximal end 354 of the nose cathetershaft 326 in the proximal direction (as indicated by arrow 356 in FIG.34) relative to the main catheter shaft 304, which is effective toretract the inner fork 332 to withdraw its prongs 342 from the openings32 in the retaining arms 30 of the prosthetic valve (FIG. 37).Retraction of the main catheter shaft 304 retracts the outer fork 330 tocompletely disconnect the prosthetic valve from the retaining mechanism306 (as shown in FIG. 37). Thereafter, the retaining mechanism can beretraced back into the sheath 322, the delivery apparatus can bewithdrawn from the body, leaving the prosthetic valve implanted withinthe native valve (such as shown in FIGS. 5A and 5B).

Because the prongs 134 of the outer fork 130 (and the prongs 336 of theouter fork 330) are relatively long and add to the rigidity of thesemi-rigid segment discussed above, it is desirable to form the prongs134 as thin as possible. However, relatively thinner prongs, althoughmore flexible, can be more susceptible to collapse if they are subjectedto compression and bending loads. To maximize the flexibility of theprongs while maintaining functionality during loading, the prongs of theouter fork can be pre-bent inwardly or outwardly. FIG. 38, for example,show an example of an outer fork 500 that has a similar construction tothe outer fork 130 except that the former has a plurality of prongs 502that are pre-bent radially inwardly toward the torque shaft at about themiddle of the prongs. Thus, under compression loading, the prongs canbend inwardly in a controlled manner and are supported by the torqueshaft and/or screw (that extends through the outer fork) to maintain thecolumn strength of the prongs. FIG. 39 shows another embodiment of anouter fork 600 that has a plurality of prongs 602 that are pre-bentradially outwardly. An outer sheath (not shown), which can be a proximalextension of a sheath 106 that covers the prosthetic valve, can extendover the prongs 602. Under compression loading, the prongs 602 can bendoutwardly and contact the sheath to maintain column strength.

FIG. 40 shows a torque shaft 700 (also referred to as a “necklace” shaftdue to its construction that resembles a necklace), according to anotherembodiment, that can be used in the any of the delivery apparatusesdisclosed herein. As shown, the torque shaft 700 comprises one or moresections 701 that comprise a plurality of annular metal links 702connected to each other in series. Each link 702 comprises a generallycircular band having alternating distally extending legs 704 andproximally extending legs 706. The gap between adjacent legs forms areceiving space for receiving a leg of an adjacent link. In theillustrated embodiment, each leg 704, 706 and receiving space has agenerally trapezoidal shape, although other shapes can be used. Theconnection between adjacent links allows the torque shaft to bend in anydirection and allows torque to be transmitted along the length of theshaft. FIG. 41 shows a cut pattern for forming the links of the torqueshaft. The shaft can be formed by laser cutting the links in a metaltube. Post-cutting etching can be used to widen the gaps betweenadjacent legs 704, 706 to achieve the desired flexibility of the shaft.

In the embodiment shown in FIG. 40, the torque shaft 700 comprises adistal segment 701 a and a proximal segment 701 b comprised of aplurality of interconnected links. The illustrated shaft 700 alsoincludes an intermediate section 710 comprising a plurality of slots orgaps laser cut or otherwise formed in the shaft, similar to the distalsegment 126 of the outer shaft 104. It should be appreciated that theentire length or substantially the entire length of the torque shaft(from the handle to the screw 112) can be formed from a plurality ofinterconnected links 702. In alternative embodiments, selected portionsof the torque shaft can be formed from interconnected metal links thatare connected to portions of the torque shaft that are comprised of oneor more polymeric layers.

Turning now to FIG. 42, there is shown a prosthetic valve 10 secured tothe distal end of a catheter assembly via a valve-retaining mechanismincluding an outer fork 130 and an inner fork 132. The threaded nut 150can be seen positioned between the prongs of the outer fork 130. Theprosthetic valve 10 is ready to be compressed and loaded into the sheath106 of a delivery apparatus. FIGS. 43-45 illustrate one embodiment of aloading cone, indicated at 800, and a method for loading the prostheticvalve 10 into the sheath 106 using the loading cone 800.

As shown, the loading cone 800 in the illustrated embodiment has aconical first section 802, an elongated cylindrical second section 804,a relatively short conical third section 806, and an elongated conicalfourth section 808. The first section defines the inlet opening of theloading cone while the fourth section defines the outlet opening of theloading cone. The fourth section 808 can be formed with a plurality ofaxial slits that define flexible legs 810 at the outlet opening of theloading cone.

In use, the proximal end of the catheter assembly is inserted into theinlet opening and pulled through the outlet opening of the loading coneso as to place the prosthetic valve partially in the first section 802,as depicted in FIG. 43. The catheter assembly is then further pulled topull the prosthetic valve into the second section 804 to partiallycompress the prosthetic valve. At this point, the user can visuallyinspect the valve leaflets, valve skirt, the valve-retaining mechanism,and other components and make any adjustments before final compressionof the prosthetic valve. For example, the user can remove any folds inthe valve leaflets or skirt to minimize damage to these components whenthe prosthetic valve is fully compressed and to ensure the prostheticvalve is further compressed in an even and predictable manner.

After making any adjustments, the prosthetic valve can be pulled throughthe third section 806 into the fourth section 808, which compresses theprosthetic valve close to its final compressed size, until the threadednut 150 is pulled outwardly from the outlet of the loading cone, asdepicted in FIG. 44. The flexible legs 810 can expand as the nut 150 isbeing pulled through the outlet of the loading cone. The third section806 serves as a transition region that facilitates movement of theprosthetic valve from the second section into the fourth section. Atthis point, the sheath 106 (positioned outside the cone 800 and to theleft of the nut 150 in the figures) can be connected to the threaded nut150 by sliding the sheath onto the nut until the raised leg portions 154of the nut snap into corresponding openings 172 in the sheath 106. Asshown in FIG. 45, a ring 814 can then be placed over the legs 810 at theoutlet of the loading cone to ensure that the diameter of the outletremains slightly smaller than the inner diameter of the sheath 106 whenthe prosthetic valve is pulled out of the loading cone and into thesheath. Finally, the distal end of the sheath 106 can be placed againstthe outlet of the loading cone and the fully compressed prosthetic valvecan be pulled into the sheath.

FIG. 46 shows another embodiment of a loading cone, indicated at 900.The loading cone 900 is similar to the loading cone 800 but has moregradual transitions between the different sections of the loading cone.

FIGS. 47 and 48 show an alternative embodiment of a sheath, indicated at1000. The sheath 1000 can have a construction similar to the sheath 106previously described, except that the sheath 1000 has a plurality ofcircumferentially spaced, flexible flaps 1002 at its distal end. Theflaps 1002 desirably are biased inwardly (as shown in FIG. 48) and canexpand radially outwardly when a prosthetic valve is deployed throughthe distal opening of the sheath (FIG. 49). FIG. 48 shows the distal endof the sheath 1000 abutting the end of a nose cone 122 for deliverythrough a patient's vasculature. The nose cone 122 in this embodimentcan have a reinforcing ring 1004 at its proximal end. As the deliverycatheter is advanced through the patient's vasculature, the flaps 1002serve as an atraumatic transition region between the end of the sheathand the nose cone to help prevent damage to surrounding tissue thatmight otherwise occur from contact with the distal end of the sheath.

FIG. 50 shows another embodiment of a delivery sheath, indicated at1100. Instead of having distal flaps, the sheath 1100 includes aflexible polymeric sleeve 1102 that is bonded to the inner surface of anouter, cylindrical metal tube 1104 and extends outwardly from the distalend of the metal tube 1104. The sleeve 1102 can made of polyethyleneterephthalate (PET) or similar polymeric materials. The sleeve 1102serves as an atraumatic transition between the sheath and a nose conethat protects surrounding tissue from contacting the metal edge of thesheath. Also, because the sleeve 1102 prevents direct contact betweenthe prosthetic valve and the distal edge of the sheath, the sleeve 1102reduces sliding friction on the prosthetic valve. As a result,significantly less force is needed retrieve the prosthetic valve afterit is deployed from the sheath (i.e., the force required to slide thesheath back over the prosthetic valve after it is deployed in thepatient). In some cases it may be necessary to re-track the distal endof the delivery apparatus for proper valve positioning, which mayinvolve withdrawing the distal end of the delivery apparatus from thediseased valve (e.g., withdrawing the distal end back into the aorta)and then advancing the delivery apparatus back into the diseased valve.The sleeve 1102 protects surrounding tissue from contacting the metaledge of the sheath, especially when re-crossing the diseased valve.

FIG. 51 shows a loading cone and plunger assembly for loading aprosthetic valve into the sheath of a delivery apparatus, according toanother embodiment. The assembly comprises a loading cone 1200 and aplunger 1202 that comprises an elongated shaft 1204 and a handle 1206.The loading cone 1200 in the illustrated embodiment includes a conicalfirst section 1208 defining in the inlet of the loading cone, acylindrical second section 1210, a conical third section 1212 and acylindrical fourth section 1214 defining the outlet of the loading cone.In an alternative embodiment (FIG. 52), the loading cone does not have afourth section 1214 and the outlet opening is provided at the end oftapered third section 1212.

The shaft 1204 has a diameter that is slightly smaller than the innerdiameter of the second section 1210 to allow the shaft to slide easilyinto the second section. Also, the shaft is sized such that its outerdiameter is equal to diameter of the valve stent 12 when the stent is ina partially compressed state within the second section 1210 of theloading cone. The distal end of the shaft 1204 is formed with aplurality of circumferentially spaced recesses 1216 on its outer surfacethat are adapted to receive the apexes of the stent at its inflow end 26when the stent is partially compressed. Located on the inner surface ofthe loading cone are a plurality of circumferentially spaced ribs 1218that can extend partially along the inner surface of the first section1208 and partially along the inner surface of the second section 1210.The ribs 1218 are adapted to extend partially into the cells of thestent 12 as the stent is urged into the second section 1210. In thismanner, the ribs 1218 can prevent the leaflets or skirt of theprosthetic valve from projecting outwardly through the cells of thestent as it is being compressed inside the loading cone, and thereforeprotect the leaflets and skirt from being pinched by the metal struts 16of the stent.

In use, a prosthetic valve (e.g., prosthetic valve 10) is mounted on acatheter assembly, the proximal end of which is pulled through theloading cone to place the prosthetic valve in the first section 1208.The prosthetic valve is then pulled into the second section 1210 topartially compress the prosthetic valve. Once the prosthetic valve ispartially compressed, the plunger can be used to assist in furtheradvancing through the prosthetic valve through the loading cone. Inparticular, the end of the plunger shaft is aligned axially with theprosthetic valve and the apexes of the stent are placed in recesses1216. As the prosthetic valve is pulled through the fourth section 1214and into a delivery sheath 106 (e.g., by pulling the catheter assemblyin a direction away from the loading cone), the prosthetic valve can besimultaneously pushed through the loading cone using the plunger.

As noted above, a delivery apparatus can have a motorized handle toeffect movement of the delivery sheath relative to a prosthetic valve.The motorized handle can be used to pull the prosthetic valve throughthe loading cone and into the delivery sheath. For example, after thecatheter assembly is inserted through the loading cone, the proximal endof the catheter assembly is connected to the motorized handle. Theprosthetic valve is manually pulled through the loading cone far enoughto be able to secure the delivery sheath 106 to its connection at thedistal end of the catheter assembly (e.g., nut 150). The motor is thenactivated to move the sheath distally relative to the catheter assemblyand against the outlet end of the loading cone 1200, which pulls theprosthetic valve out of the loading cone and into the sheath.

FIG. 53 illustrates a delivery apparatus 1300, according to anotherembodiment. The delivery apparatus 1300 in this embodiment includes allof the features of the delivery apparatus 300 of FIGS. 30-33 except thatit includes the torque shaft 700 shown in FIG. 40. The use of the torqueshaft 700 increases the flexibility of the portion of the deliveryapparatus that is positioned in the ascending aorta during valvedeployment. This portion of the delivery apparatus typically issubjected to the greatest amount of bending during valve deployment. Inparticular embodiments, the torque shaft 700 extends from thevalve-retaining mechanism to the handle of the delivery apparatus. Inother embodiments, the delivery apparatus can comprise a torque shaftthat has a distal segment formed from interconnected metal links 702 anda proximal segment formed from other materials (e.g., one or more layersof polymeric tubing).

FIG. 54 illustrates a delivery apparatus 1400, according to anotherembodiment. The delivery apparatus 1400 in this embodiment includes atorque shaft 700 that extends through an outer fork 330. A screw 1402 ispositioned along the length of the torque shaft at a location proximalto the outer fork 330. An outer shaft 304 (not shown in FIG. 54) isformed with internal threads that mate with the threads of the screw1402 to transform rotation of the torque shaft into axial translation ofthe sheath 322 (which is connected to the torque shaft via couplingmember 362). Desirably, the screw 1402 and the internal threads of theouter shaft are at a location along the length of the torque shaft thatis positioned in the descending aorta during valve deployment. Theextension of the torque shaft 700 distally into the area occupied by thevalve-retaining mechanism increases the overall flexibility of thisportion of the delivery apparatus.

Due to the presence of gaps in the links 702 that form the torque shaft(which allows for a limited amount of axial movement between links), theexpansion force of the prosthetic valve against the distal end of thesheath 322 can cause the prosthetic valve to “jump” slightly out of thesheath as it is being deployed. To control the expansion of theprosthetic valve as it is being deployed, a spring 1404 can beco-axially mounted over the torque shaft 700. The outer shaft 304 (notshown) extends at least partially over the spring 1404. The proximal end1406 of the spring is fixed relative to the inner surface of the outershaft 304. The distal end of the spring 1408 is positioned to contactcoupling member 362 when the torque shaft is rotated to cause the sheath322 to move proximally during valve deployment. In this manner, thespring 1404 compresses and applies a distally directed force against thecoupling member 362 and the sheath, which resists sudden movement of thesheath in the proximal direction caused by the expansion of theprosthetic valve.

FIG. 55 shows a delivery apparatus 1500, according to anotherembodiment, which is a modification of the delivery apparatus. Thisembodiment is similar to the embodiment 1300 shown in FIG. 53 exceptthat a ring, or anchoring disc, 1508 (similar to ring 128) is placed onthe torque shaft 1502 proximal to the screws. As shown, the torque shaft1502 can include a distal segment 1506 having the same construction ofshaft 700 shown in FIG. 40 and a proximal segment 1504 that can compriseone or more layers of polymeric tubing. The ring 1508 can be mountednear the distal end of the proximal segment 1504. The ring is receivedby a feature formed on the inner surface of the outer shaft 126 to allowrotation of the torque shaft but prevent axial translation of the torqueshaft relative to the outer shaft. A threaded nut 150 can be mounted onthe screw 112 in a manner similar to that shown in FIG. 21 to transformrotation of the torque shaft into axial movement of the sheath 106. Aspring 1512 can be mounted on the distal segment 1506 of the torqueshaft to contact the nut 150 and minimize valve jumping during valvedeployment.

FIG. 56 shows a delivery apparatus 1600, according to anotherembodiment. This embodiment is similar to the embodiment 1500 shown inFIG. 55, except that the ring 1508 can be placed distal to the distalsegment 1506 of the torque shaft. In the embodiment of FIG. 56, thespring 1512 can be excluded because the ring 1508 prevents the axialforce of the expanding prosthetic valve from being transmitted to thelinks in the distal segment 1506 of the torque shaft.

FIG. 57 shows a delivery apparatus 1700, according to anotherembodiment. This embodiment is similar to the embodiment 1500 shown inFIG. 55, except that it comprises a torque shaft that includes a distalsegment 1706 having the same construction of shaft 700 shown in FIG. 40and a proximal segment 1702 that includes a screw 1704 that engagesinternal threads on an outer shaft 104 (not shown). The distal segment1706 extends partially into the area occupied by the outer fork 330. Aspring 1708 can be mounted on the distal segment 1706 to minimize valvejumping as previously described. This embodiment allows the distalscrew/screws (the screw/screws distal to the segment 1706) to rotate andtranslate the nut 150 while allowing the torque shaft to translateaxially. This mechanism drives the nut 150 twice as fast as compared tothe embodiments described above. Consequently, this embodiment can use ashorter length of screw/screws to move the nut 150, and therefore canreduce the overall length of the semi-rigid segment. Moreover, thisembodiment allows the portion of the delivery apparatus occupied by thedistal segment 1706 to bend during tracking of the delivery apparatusthrough the patient's vasculature.

Known introducer sheaths typically employ a sleeve made from polymerictubing having a radial wall thickness of about 0.010 to 0.015 inch. FIG.58A shows another embodiment of an introducer sheath, indicated at 2000,that employs a thin metallic tubular layer that has a much smaller wallthickness compared to known devices. In particular embodiments, the wallthickness of the sheath 2000 is about 0.0005 to about 0.002 inch. Theintroducer sheath 2000 includes a proximally located housing, or hub,2002 and a distally extending sleeve, or cannula, 2004. The housing 2002can house a seal or a series of seals as known in the art to minimizeblood loss. The sleeve 2004 comprises a tubular layer 2006 that isformed from a metal or metal alloy, such as Nitinol or stainless steel,and desirably is formed with a series of circumferentially extending orhelically extending slits or openings to impart a desired degree offlexibility to the sleeve.

As shown in FIG. 58B, for example, the tubular layer 2006 is formed(e.g., laser cut) with an “I-beam” pattern of alternating circular bands2007 and openings 2008 with axially extending connecting portions 2010connecting adjacent bands 2007. Two adjacent bands 2007 can be connectedby a plurality of angularly spaced connecting portions 2010, such asfour connecting portions 2010 spaced 90 degrees from each other aroundthe axis of the sleeve, as shown in the illustrated embodiment. Thesleeve 2004 exhibits sufficient flexibility to allow the sleeve to flexas it is pushed through a tortuous pathway without kinking or buckling.FIG. 59 shows another pattern of openings that can be laser cut orotherwise formed in the tubular layer 2006. The tubular layer in theembodiment of FIG. 59 has a pattern of alternating bands 2012 andopenings 2014 with connecting portions 2016 connecting adjacent bands2012 and arranged in a helical pattern along the length of the sleeve.In alternative embodiments, the pattern of bands and openings and/or thewidth of the bands and/or openings can vary along the length of thesleeve in order to vary stiffness of the sleeve along its length. Forexample, the width of the bands can decrease from the proximal end tothe distal end of the sleeve to provide greater stiffness near theproximal end and greater flexibility near the distal end of the sleeve.

As shown in FIG. 60, the sleeve can have a thin outer layer 2018extending over the tubular layer 2006 and made of a low frictionmaterial to reduce friction between the sleeve and the vessel wall intowhich the sleeve is inserted. The sleeve can also have a thin innerlayer 2020 covering the inner surface of the tubular layer 2006 and madeof a low friction material to reduce friction between the sleeve and thedelivery apparatus that is inserted into the sleeve. The inner and outerlayers can be made from a suitable polymer, such as PET, PTFE, and/orFEP.

In particular embodiments, the tubular layer 2006 has a radial wallthickness in the range of about 0.0005 inch to about 0.002 inch. Assuch, the sleeve can be provided with an outer diameter that is about1-2 Fr smaller than known devices. The relatively smaller profile of thesleeve 2004 improves ease of use, lowers risk of patient injury viatearing of the arterial walls, and increases the potential use ofminimally invasive procedures (e.g., heart valve replacement) forpatients with highly calcified arteries, tortuous pathways or smallvascular diameters.

In a modification of the introducer sheath 2000, the sheath can haveinner and outer layers 2020, 2018, respectively, which are secured to ametal sleeve (e.g., sleeve 2004) only at the proximal and distal ends ofthe metal sleeve. The inner and outer polymeric layers can be bonded tothe metal sleeve (or to each other through the gaps in the metalsleeve), for example using a suitable adhesive. In this manner, themetal sleeve is unattached to the inner and outer polymeric layersbetween the proximal and distal ends of the sleeve along the majority ofthe length of the sleeve, and therefore is “free-floating” relative tothe polymeric layers along the majority of the length of the sleeve.This construction allows the adjacent bands of metal to bend more easilyrelative to the inner and outer layers, providing the sheath withgreater flexibility and kink-resistance than if the inner and outerlayers are bonded along the entire length of the sleeve.

FIG. 61 shows a segment of an alternative metal sleeve, indicated at2100, that can be used in the introducer sheath 2000. The sheath 2000 inthis embodiment desirably includes inner and outer polymeric layers,which desirably are secured to the metal sleeve only at its proximal anddistal ends as discussed above. The sleeve 2100 includes circular bands2102 connected by two links, or connecting portions, 2104, extendingbetween two adjacent rings. Each pair of links connecting two adjacentbands 2102 desirably are spaced 180 degrees from each other anddesirably are rotationally offset 90 degrees from an adjacent pair oflinks, which allows for multi-axial bending.

FIG. 62 shows a segment of another embodiment of a metal sleeve,indicated at 2200, that can be used in the introducer sheath 2000. Thesleeve 2200 has the same cut pattern as the sleeve 2100, and thereforehas circular bands 2202 and two links 2204 connecting adjacent bands,and further includes two cutouts, or apertures, 2206 formed in each band2202 to increase the flexibility of the sleeve. The cutouts 2206desirably have a generally elliptical shape, but can have other shapesas well. Each cutout 2206 desirably extends about 180 degrees in thecircumferential direction of the sleeve and desirably is rotationaloffset about 90 degrees from a cutout 2206 in an adjacent band 2202.

In particular embodiments, the metal sleeve of an introducer sheath hasa wall thickness in the range of about 0.002 inch to about 0.006 inch.In one implementation, a sheath has a metal sleeve having a wallthickness of about 0.002 inch and an inner diameter of about 0.229 inch,an inner polymeric layer having a wall thickness of about 0.0025 inch,an outer polymeric layer having a wall thickness of about 0.001 inch,and a total wall thickness (through all three layers) of about 0.0055inch. In another implementation, a sheath has a metal sleeve having awall thickness of about 0.004 inch and an inner diameter of about 0.229inch, an inner polymeric layer having a wall thickness of about 0.0025inch, an outer polymeric layer having a wall thickness of about 0.001inch, and a total wall thickness (through all three layers) of about0.0075 inch. FIG. 63 shows the cut pattern for forming the metal sleeve2100 of FIG. 61. FIG. 64 shows the cut pattern for forming the metalsleeve 2200 of FIG. 62. FIG. 65 shows the same cut pattern as FIG. 64but includes cutouts 2206 that are narrower than shown in FIG. 64.

TABLE 1 Minimum Minimum bend Wall bend radius radius allowing thicknessof without visual passage of 16-Fr metal sleeve Material kink dilator.004″ Nitinol 1″ 1″ .004″ Stainless steel 1″ 1″ .002″ Nitinol 6″ 1″.002″ Stainless steel 6″ 1″ .002″ Stainless steel (wide 2″ 1″ rings)

Table 1 above demonstrates the bend performance of several metalsleeves. Each metal sleeve had an inner diameter of about 0.229 inch.Each sleeve was formed with the cut pattern shown in FIG. 62, except forthe last sleeve in Table 1, which was formed with the cut pattern shownin FIG. 61. Table 1 indicates that all of the sleeves providingdeliverability at a relatively small bend radius (1 inch). Furthermore,it was found that the metal sleeves can recover their circularcross-sectional shapes even after passing a delivery device through avisibly kinked section of the sleeve.

FIGS. 66-67 show an alternative configuration for the screw 112 and nut150 of the delivery apparatus 100. In this embodiment, the screw 112 isreplaced with a helical coil 2300 (which can be, for example, a metalcompression or tension spring), and the nut 150 is replaced with asheath retaining ring in the form of a washer, or blade, 2302 mounted onthe coil 2300. The proximal end of the coil is fixedly secured to thedistal end of the torque shaft 110 (for example by welding or a suitableadhesive). The coil 2300 can be made of any of various suitable metals(e.g., stainless steel, Nitinol, etc.) or polymeric materials.

The washer 2302 has a central aperture 2304 that receives the coil 2300and an internal tooth 2306 that engages the grooves defined on the outersurface of the coil and desirably extends radially inwardly betweenadjacent turns or loops of the coil. The outer circumferential edge ofthe washer 2302 can be formed with a plurality of recesses, or grooves,2308, each of which is sized to receive a prong 134 of the outer fork130, which prevents rotation of the washer upon rotation of the torqueshaft 110. The sheath 106 can be secured to the outer circumferentialedge of the washer 2302 in any convenient manner. For example, theportions between recesses 2308 can extend into the openings 172 of thesheath (FIG. 18) to fix the sheath axially and rotationally relative tothe washer. Alternatively, the washer can be welded or adhesivelysecured to the sheath.

When incorporated in the delivery apparatus 100, the coil 2300 andwasher 2302 operate in a manner similar to the screw 112 and nut 150.Thus, when the torque shaft 110 is rotated, the washer 2302 is caused tomove axially along the length of the coil 2300 to effect correspondingaxial movement of the sheath, either to deploy a prosthetic valve orrecapture a prosthetic valve back into the sheath. An advantage of thecoil and washer configuration is that it allows the distal portion ofthe delivery apparatus occupied by the coil to bend or flex tofacilitate tracking through the patient's vasculature, especially inpatients with relatively small aortic arches and short ascending aortas.The coil also allows the sheath to be moved (proximally or distally)upon rotation of the torque shaft when the coil is in a flexed or curvedstate inside the patient's vasculature. In particular embodiments, thedistal portion of the delivery apparatus occupied by the coil can beflexed from a straight configuration to a curved configuration having aradius of curvature of about 1 cm. In addition, the coil can change itspitch under dynamic loading (compression or tension), which reduces thebuild-up of tensile forces along the length of the delivery apparatusand avoids galling of the washer when subjected to bending forces.

The coil and washer configuration can be implemented in other deliveryapparatuses that are used to implant various other types of prostheticimplants within body ducts. For example, the coil and washerconfiguration can be incorporated in a delivery apparatus used toimplant stents or similar implants within the coronary sinus. The coiland washer configuration can also be utilized in various non-medicalapplications to replace a screw and nut assembly where the screw issubjected to bending forces.

FIG. 68 shows an alternative embodiment of a stent 2400 that can beincorporated in a prosthetic heart valve, such as prosthetic valve 10.Thus, a leaflet assembly (e.g., leaflet assembly 14) can be mounted tothe stent to form a prosthetic heart valve. Although FIG. 68 shows aflattened view of the stent, one skilled in the art will appreciate thatthe stent has an annular configuration, which can be substantiallycylindrical or can be shaped to have a diameter that varies along thelength of the stent (similar to stent 12). The stent 2400 can be made ofvarious self-expandable materials (e.g., Nitinol) or plasticallyexpandable materials (e.g., stainless steel), as known in the art.

The stent 2400 is configured to facilitate recapture of a prostheticvalve once fully deployed from a delivery sheath (e.g., sheath 106). Asshown in FIG. 68, the stent has a first end 2402 (typically the outflowend of the stent) and a second end 2404 at the opposite end of the stent(typically the inflow end of the stent). The first end 2402 isconfigured to be releasably connected to a delivery apparatus. Thus,similar to stent 12, the stent 2400 has a plurality of retaining arms2406, each having a corresponding opening 2408. The retaining arms 2406of the stent 2400 can be releasably secured to the delivery apparatus100 using the valve-retaining mechanism 114 comprised of the outer andinner forks 130, 132 described above. As can be seen, the stent 2400 isformed without any struts that form free apexes that point in thedirection of the first end 2402, except for the retaining arms 2406. Inother words, except for the retaining arms 2406, the stent comprises aplurality of apexes 2410 pointing in the direction of the first end,with each such apex 2410 being formed by two struts 2412 a, 2412 b inthe same row of struts and at least a third strut 2412 c in an adjacentrow. Thus, each apex 2410 pointing in the direction of the first end2402 are retained from flexing or bending outwardly relative to adjacentapexes. In contrast, the stent also can be formed with a plurality offree apexes 2414 pointing in the direction of the second end 2404 of thestent. The free apexes 2414 are not restrained from relative flexinglike fixed apexes 2410.

In use, the retaining arms 2406 of the stent can be secured to thedelivery apparatus 100 in the manner described above for delivery to animplantation site within a patient. When the delivery sheath 106 isretracted, the prosthetic valve self-expands to its expandedconfiguration (similar to prosthetic valve 10 shown in FIG. 36 or FIG.42). If it becomes necessary to recapture the prosthetic valve back intothe delivery sheath, such as to reposition the prosthetic valve or fullywithdraw the prosthetic valve from the patient, the delivery apparatuscan be operated to pull the prosthetic valve back into the sheath ormove the sheath distally over the prosthetic valve. Because the stent2400 does not include any free apexes pointing in the direction of thefirst end 2402, except for the retaining arms (which are secured to thedelivery apparatus), the sheath can slide easily over the stent withoutcatching any apexes of the stent. In other words, all of the apexespointing toward the distal end of the delivery sheath are restrictedfrom flexing or bowing outward into the path of travel of the deliverysheath as it is pushed back over the stent.

The stent 2400 is shown as having three free apexes/retaining arms 2406at the first end of the stent, although this is not a requirement. Thenumber of free apexes at the first end can vary, but desirably is equalto the number of prongs on each of the inner and outer forks of thevalve-retaining mechanism so that each free apex at the first end 2402can be secured to the valve-retaining mechanism. Also, the number offree apexes 2414 at the second end 2404 can vary. Table 2 below showsvarious combinations of inflow free apexes 2414, number of rows ofstruts, and outflow free apexes 2406 that can be implemented in a stent.As mentioned above, the stent of a prosthetic valve typically is securedto a delivery apparatus at the outflow end of the stent (in which casethe first end 2402 is the outflow end of the stent). If the prostheticvalve and the delivery catheter are designed to secure the inflow end ofthe stent to the delivery catheter, then the stent can have the sameconstruction except that the first end 2402 is the inflow end of thestent and the second end 2404 is the outflow end of the stent. In anycase, the number of struts and apexes in each row of struts generallyincreases moving in a direction from the first end 2402 to the secondend 2404.

If the prosthetic valve is intended to be secured to a deliveryapparatus at the inflow or outflow end of the stent, then the stent canhave a configuration in which the number of apexes in each row increasesfrom the first end 2402 to the middle of the stent and then decreasesfrom the middle to the second end 2404 of the stent. In particularembodiments, the stent can have a configuration that is symmetrical withrespect a line that extends through the middle of the stent(perpendicular to the flow axis) and the number of apexes in each rowincreases from the first end 2402 to the middle of the stent and thendecreases from the middle to the second end 2404 of the stent.

FIGS. 69-72 show alternative embodiments of stents formed from aplurality of struts without any free apexes pointing in a directiontoward one end of the stent, except for retaining arms 2406. The stentsillustrated in FIGS. 68-72 also can be implemented in prostheticimplants other than prosthetic valves, such as stent grafts or barestents implanted in various ducts or lumens within the body.

TABLE 2 Outflow Cell # Inflow Cell # # of Rows of (Outflow Free (InflowFree Apexes) Struts Apexes/retaining arms) 9 5 3 9 5 6 12 5 3 12 6 3 125 6 15 5 3 15 6 3 15 5 6 18 5 3 18 5 6 15 7 5

FIGS. 73-87 show the components of a system that can be used to connecta prosthetic valve 10 to a delivery apparatus 100 and to partially crimpthe prosthetic valve for packaging the prosthetic valve and deliveryapparatus assembly. The system generally includes a storage tubeassembly 3000 (FIGS. 73-75), a transfer tube 3006 (FIGS. 76-77), anattachment spacer 3008 (FIGS. 78-80), an attachment tool 3018 (FIGS.81-83), an attachment plunger 3034 (FIGS. 84-85), and a sleeve 3038(FIGS. 86-87).

These components will be described in detail below in connection with amethod for attaching the prosthetic valve 10 to the delivery apparatus100 and a method for partially crimping the prosthetic valve and storingthe prosthetic valve in the partially crimped state for final packagingof the prosthetic valve and delivery apparatus assembly. Referring firstto FIG. 88, the storage tube assembly 3000, which comprises a frontstorage portion 3002 and a back storage tube portion 3004, is slid ontothe distal end portion of the delivery apparatus. The storage tubeassembly 3000 will be used later to store the prosthetic valve 10 in apartially crimped state for final packaging of the prosthetic valve anddelivery apparatus assembly. Referring next to FIG. 89, following thestorage tube assembly, the transfer tube 3006 is slid onto the distalend portion of the delivery apparatus and the nose catheter shaft 120 ispulled distally away from the sheath 106 a few inches.

Referring next to FIGS. 90-91, the attachment spacer 3008 is placed onthe nose cone shaft 120. As best shown in FIGS. 78-80, the attachmentspacer 3008 comprises a plurality of proximal prongs, or tridents, 3010extending from an intermediate hub portion 3014, and a plurality oflongitudinally extending slots 3012 defined between adjacent prongs3010. Extending from the opposite end of the hub portion are twoelongated distal prongs 3016. As shown in FIGS. 90-91, the proximalprongs 3010 are radially compressed slightly by squeezing them towardeach other and slid underneath the distal end portions of the prongs 134of the outer fork 130. The distal end portion of each prong 134 isaligned with a respective slot 3012 and placed between a pair ofadjacent prongs 3010 such that the side edges of each prong 134 can restwithin recessed portions 3013 of the pair of adjacent prongs 3010 of theattachment spacer (see FIGS. 80 and 91).

Referring next to FIGS. 92-93, the attachment tool 3018 is placed aroundthe sheath 106 and the attachment spacer 3008. The attachment tool 3018can comprise two separable housing portions 3020. When the two housingportions 3020 are placed together (FIG. 93), two locking clips 3022 canbe placed on opposite side edges on the tool to hold the two housingportions together. The assembled attachment tool 3018 defines agenerally cylindrical proximal portion 3024 that surrounds the deliverysheath 106 and a generally cylindrical, enlarged distal portion 3026sized to receive the prosthetic valve 10 when the prosthetic valve is inan expanded state. As shown in FIG. 94, the attachment tool 3018 hasthree angularly spaced apertures, or windows, 3028 located at the areawhere the proximal portion 3024 begins to transition into the enlargeddistal portion 3026. Each prong 134 of the outer fork 130 is alignedwithin a respective window 3028 such that the opening 140 of each prong134 is centered within a corresponding window 3028, as shown in FIG. 94.As shown in FIG. 95, a bottom locking component 3030 is slid over andplaced around the proximal portion 3024. The locking component 3030 canapply sufficient pressure to the proximal portion to retain theattachment tool relative to the sheath 106. As shown in FIG. 96, theprongs 136 of the inner fork 132 are rotational aligned with the prongs134 of the outer fork. The shaft 120 is then pulled in the proximaldirection (toward the proximal portion 3024 of the attachment tool, asindicated by arrow 3032) until the inner prongs 136 are at a locationproximal to the windows 3028 in the attachment tool. As shown in FIG.112, the prongs 136 of the outer fork 132 can have outwardly curveddistal end portions 136 a that generally define a cone shape tofacilitate insertion of the outer prongs 136 to the stent retaining arms30.

Referring next to FIG. 97, the prosthetic valve 10 is mounted on anattachment plunger 3034 by aligning the commissures of the prostheticvalve with respective guide rails 3036 (see also FIG. 85) of the plungerand partially inserting the inflow end of the prosthetic valve into anopening at the proximal end of the plunger. The inside surface adjacentthe opening of the plunger can be formed with small recesses 3037 (FIG.85) sized to receive the apexes of the stent 12 of the prosthetic valve.The prosthetic valve 10 can pressed into the plunger so that the apexesof the stent snap into the recesses in the plunger. Referring to FIG.98, the protective tubular sleeve 3038 is inserted through the plunger3034 and the prosthetic valve 10 until a proximal end portion 3040 ofthe sleeve extends slightly beyond the outflow end of the prostheticvalve 10 (FIG. 99). The sleeve 3038 shields the leaflets of theprosthetic valve during the subsequent step of securing the prostheticvalve to the delivery apparatus.

FIGS. 99 and 100 show the plunger and the attachment tool being used tosecure the prosthetic valve 10 to the delivery apparatus. As shown inFIG. 99, the distal prongs 3016 of the attachment spacer 3008 areinserted into the proximal end portion 3040 of the sleeve 3038, andresilient locking arms 3042 of the plunger are rotational aligned withmating openings 3044 of the attachment tool. Thereafter, as shown inFIG. 100, the prosthetic valve 10 and the plunger 3034 are pressed intothe attachment tool 3018 until the locking arms 3042 extend over andsnap into place behind locking tabs 3046 on the attachment tool. Theaction of pushing the prosthetic valve into the attachment tool causesthe retaining arms 30 of the prosthetic valve to slide along the innersurface of distal portion 3026 of the attachment tool and then inwardlythrough respective openings 140 in the prongs 134 of the outer fork (seeFIG. 113). As best shown in FIG. 83, the inside surface of theattachment tool can be formed with three angularly spaced grooves 3045aligned with windows 3028 to assist in guiding the retaining arms 30 ofthe stent along the inner surface of the attachment tool and through theopenings 140 of the prongs 134. At this stage, as shown in FIG. 101, thenose cone shaft 120 is advanced distally (in the direction of arrow3048, which causes the prongs 136 of the inner fork to extend throughthe openings 32 in the retaining arms 30 of the prosthetic valve,thereby securing the prosthetic valve to the delivery apparatus (seealso FIG. 113). Once the prosthetic valve is secured to the deliveryapparatus, the attachment tool, the plunger, and the attachment spacercan be removed from the delivery apparatus.

Referring next to FIG. 102, the transfer tube 3006 (previously placed onthe delivery apparatus), is moved to a position adjacent the prostheticvalve. Then, as shown in FIG. 103, the prosthetic valve 10 and anenlarged end portion 3019 of the transfer tube are inserted into theaperture of a valve crimper 3050. The valve crimper 3050 is used tocrimp (radially compress) the prosthetic valve to a partially crimpedstate so that the partially crimped prosthetic valve can be pulled intothe main cylinder 3052 of the transfer tube. A partially crimped statemeans that the prosthetic valve is radially compressed from its fullyexpanded state to a state between its fully expanded state and its fullycompressed state in which the prosthetic valve can fit inside thedelivery sheath 106.

As shown in FIG. 105, the main cylinder 3052 has a plurality of leaflettucking windows 3054. Using a tucking tool 3056 (FIG. 106), a user caninsert the tucking tool 3056 through windows 3054 and into theindividual cells of the stent 12 to make sure all leaflet and skirtmaterial is “tucked” inside of the metal struts of the stent. As shownin FIGS. 107 and 108, the back storage tube portion 3004 is theninserted into the main cylinder 3052 of the transfer tube. Finally, asshown in FIGS. 109 and 100, a cap portion 3005 is placed on an extensionportion 3007 of the back storage tube portion 3004, and the frontstorage tube portion 3002 is secured to the back storage tube portion3004. As best shown in FIG. 74, the front storage tube portion 3002 canhave locking tabs 3060 that are received in corresponding slots 3062 onthe back storage tube portion 3004. Portions 3002 and 3004 can besecured together by inserting tabs 3060 into slots 3062 and twistingportion 3002 to establish a snap fit connection between these twocomponents.

FIG. 111 shows the prosthetic valve 10 inside the back storage tubeportion 3004 and the delivery sheath 106 extending partially into theopposite end portion of the back storage tube portion. As shown, theinner surface of the storage tube assembly is formed with a taperedsurface 3064 extending from an inner bore 3066 containing the prostheticvalve to an inner bore 3068 having a reduced diameter containing thesheath 106. The tapered surface 3064 helps guide and fully crimp theprosthetic valve as it is pulled within the sheath 106. The opening ofthe bore 3068 closest to the tapered surface is formed with an annularlip 3070 that abuts the distal end of the sheath 106.

In particular embodiments, the assembly comprising the deliveryapparatus 100, the storage tube assembly 3000, and the partially crimpedprosthetic valve 10 (inside bore 3066) can be packaged together in asterile package enclosing all of these components. The packagecontaining these components can be supplied to end users for storage andeventual use. In particular embodiments, the leaflets 34 of theprosthetic valve (typically made from bovine pericardium tissue or othernatural or synthetic tissues) are treated during the manufacturingprocess so that they are completely or substantially dehydrated and canbe stored in a partially or fully crimped state without a hydratingfluid. In this manner, the package containing the prosthetic valve andthe delivery apparatus can be free of any liquid. Methods for treatingtissue leaflets for dry storage are disclosed in U.S. Pat. No. 8,007,992and U.S. Patent Publication No. 2009/0164005, filed Dec. 18, 2008, bothof which documents are incorporated herein by reference.

When the surgeon is ready to implant the prosthetic valve in a patient,the delivery apparatus 100, the partially crimped prosthetic valve 10,and the storage tube assembly 3000 can be removed from the package whileinside the operating room. The prosthetic valve 10 can be loaded intothe sheath 106 by rotating the torque shaft 110 in a direction to urgethe sheath 106 against the annular lip 3070, which causes the prostheticvalve to slide into the sheath 106. If a motorized handle is provided(as described above), the torque shaft can be rotated by actuating themotor of the handle. Once the prosthetic valve is inside the sheath, thestorage tube assembly 3000 can be removed from the delivery apparatus,which is now ready for insertion into the patient. As can beappreciated, storing the prosthetic valve in a partially crimped stateinside the storage tube assembly eliminates the task of connecting theprosthetic valve to the delivery apparatus and greatly simplifies thecrimping process for the surgeon.

In an alternative embodiment, the prosthetic valve, once attached to thedelivery apparatus, can be partially crimped using a loading cone tool,such as shown in FIGS. 51-52. The prosthetic valve can be stored in apartially crimped state inside the loading cone (e.g., with the section1210 of cone 1200), which can be packaged together with the deliveryapparatus. When the delivery apparatus and prosthetic valve are to beused, the surgeon can remove the assembly from the package and load theprosthetic valve into the sheath 106, such as by activating the torqueshaft, which causes the prosthetic valve to be pulled from the loadingcone into the sheath.

In additional embodiments, the leaflets of the prosthetic valve can betreated for wet storage of the prosthetic valve, in which case thepartially crimped prosthetic valve along with the component retainingthe prosthetic valve in the partially crimped state (e.g., a loadingcone or the storage tube assembly described above) can be placed in asealed storage container containing a hydrating fluid for the leaflets.If the prosthetic valve is pre-mounted to the delivery apparatus asdescribed above, the packaging for the delivery apparatus and theprosthetic valve can include a sealed storage container with a hydratingfluid (a wet storage compartment) containing the prosthetic valve, thecomponent retaining the prosthetic valve, and the distal end portion ofthe delivery apparatus. The remaining portion of the delivery apparatuscan extend out of the wet storage compartment into a dry storagecompartment of the packaging. A method for treating tissue leaflets forwet storage are disclosed in U.S. Pat. No. 7,579,381, which isincorporated herein by reference.

In other embodiments, the prosthetic valve can be pre-mounted on thedelivery apparatus as described above but is not pre-crimped, andinstead is packaged together with the delivery apparatus with theprosthetic valve in its fully expanded state (either in a wet or drystorage compartment).

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Moreover,additional embodiments are disclosed in U.S. Patent ApplicationPublication No. 2010/0049313 (U.S. application Ser. No. 12/429,040),which is incorporated herein by reference. Accordingly, the scope of theinvention is defined by the following claims. We therefore claim as ourinvention all that comes within the scope and spirit of these claims.

We claim:
 1. A prosthetic heart valve comprising: a self-expanding stenthaving an inflow end, an outflow end, and a plurality of interconnectedstruts, wherein the struts define a first row of cells disposedproximate the inflow end, a second row of cells disposed closer towardthe outflow end than the first row of cells, a third row of cellsdisposed closer toward the outflow end than the second row of cells, anda fourth row of cells disposed closer toward the outflow end than thethird row of cells and disposed adjacent the outflow end, wherein thefirst row of cells includes more cells than the fourth row of cells,wherein cells of the third row of cells are larger than cells of thefirst row of cells, wherein cells of the fourth row of cells are largerthan the cells of the first row of cells and the cells of the third rowof cells, wherein the struts defining the fourth row of cells have firstend portions directed toward the inflow end, second end portionsdirected toward the outflow end, and intermediate portions disposedbetween the first end portions and the second end portions, wherein thestruts of adjacent cells of the fourth row of cells are connected at theintermediate portions of the struts, wherein the stent includes a firstdiameter at the inflow end, a second diameter at a location disposedtoward the outflow end of the stent relative to the first diameter, anda third diameter at a location disposed toward the outflow end of thestent relative to the second diameter, and wherein the second diameteris less than the first diameter and less than the third diameter; aleaflet assembly coupled to the stent and having a plurality ofleaflets, wherein the leaflets are configured to allow blood to flowthrough the prosthetic heart valve in one direction from the inflow endto the outflow end of the stent; and a skirt secured to the struts ofthe stent.
 2. The prosthetic heart valve of claim 1, further comprisinga plurality of retaining arms extending from the struts of the fourthrow of cells, wherein the retaining arms having openings formed thereinconfigured for releasably securing the prosthetic heart valve to adelivery apparatus.
 3. The prosthetic heart valve of claim 1, whereinthe first row of cells includes more cells than the third row of cells.4. The prosthetic heart valve of claim 1, wherein the first row of cellscomprises 9-18 cells.
 5. The prosthetic heart valve of claim 1, whereinthe stent comprises a shape memory material.
 6. The prosthetic heartvalve of claim 1, wherein each cell of the first row of cells shares twostruts with an axially-adjacent cell of the second row of cells.
 7. Theprosthetic heart valve of claim 1, wherein each cell of the fourth rowof cells shares one strut with an axially-adjacent cell of the third rowof cells.
 8. The prosthetic heart valve of claim 1, wherein the cells ofthe first, second, third, and fourth rows of cells are diamond shaped.9. A prosthetic heart valve comprising: a self-expanding frame having aninflow end portion, an outflow end portion, and a plurality ofinterconnected frame members, wherein the frame members define a firstrow of cells disposed adjacent the inflow end portion, a second row ofcells disposed closer to the outflow end portion than the first row ofcells, and a third row of cells disposed between the second row of cellsand the outflow end portion, wherein the third row of cells includesfewer cells than the first row of cells and fewer cells than the secondrows of cells, wherein cells of the third row of cells are larger thancells of the first row of cells and cells of the third row of cells,wherein the cells of the third row of cells have first end portionsdirected toward the inflow end portion, second end portions directedtoward the outflow end portion, and intermediate portions disposedbetween the first end portions and the second end portions, whereinadjacent cells of the third row of cells are connected at theintermediate portions, wherein the frame includes a first diameter atthe inflow end portion, a second diameter at a location closer to theoutflow end portion than the first diameter, and a third diameter at alocation closer to the outflow end portion than the second diameter, andwherein the second diameter is less than the first diameter and lessthan the third diameter; and a leaflet assembly coupled to the frame andhaving a plurality of leaflets, wherein the leaflets are configured toallow blood to flow through the prosthetic heart valve in one directionfrom the inflow end portion to the outflow end portion of the frame. 10.The prosthetic heart valve of claim 9, further comprising a plurality ofretaining arms extending from the third row of cells, wherein theretaining arms include openings formed therein configured for releasablysecuring the prosthetic heart valve to a delivery apparatus.
 11. Theprosthetic heart valve of claim 9, further comprising a fourth row ofcells disposed between the second row of cells and the third row ofcells.
 12. The prosthetic heart valve of claim 11, wherein each cell ofthe fourth row of cells shares a first frame member with a firstaxially-adjacent cell of the third row of cells and shares a secondframe member with a second axially-adjacent cell of the third row ofcells.
 13. The prosthetic heart valve of claim 11, wherein the fourthrow of cells includes fewer cells than the first row of cells and fewercells than the second rows of cells.
 14. The prosthetic heart valve ofclaim 9, wherein the first row of cells comprises 9-18 cells.
 15. Aprosthetic heart valve comprising: a stent having an inflow end, anoutflow end, a plurality of interconnected struts, and a plurality ofretaining arms, wherein the stent is formed from a shape memory materialsuch that the stent is self-expandable from a radially-compressed stateto a radially-expanded state, wherein the struts form a first row ofcells disposed adjacent the inflow end, a second row of cells disposedfarther toward the outflow end than the first row of cells, a third rowof cells disposed farther toward the outflow end than the second row ofcells, and a fourth row of cells disposed between the third row of cellsand the outflow end, wherein the fourth row of cells includes fewercells than the first row of cells and fewer cells than the second row ofcells, wherein cells of the first row of cells are smaller than cells ofthe third row of cells and smaller than cells of the fourth row ofcells, wherein cells of the second row of cells are smaller than thecells of the third row of cells and smaller than the cells of the fourthrow of cells, wherein the cells of the third row of cells are smallerthan the cells of the fourth row of cells, wherein the cells of thefourth row of cells have first end portions directed toward the inflowend, second end portions directed toward the outflow end, andintermediate portions disposed between the first end portions and thesecond end portions, wherein adjacent pairs of cells of the fourth rowof cells are connected at the intermediate portions, and wherein theretaining arms extend from the second end portions of the fourth row ofcells, wherein the retaining arms have openings formed therein; and aleaflet assembly coupled to the stent and having a plurality ofleaflets, wherein the leaflets are configured to allow blood to flowthrough the prosthetic heart valve in one direction from the inflow endto the outflow end of the stent.
 16. The prosthetic heart valve of claim15, the cells of the first row of cells are the same size as the cellsof the second row of cells.
 17. The prosthetic heart valve of claim 15,wherein the struts are arranged in circumferentially-extending rows ofangled struts arranged end-to-end in a zig-zag pattern.
 18. Theprosthetic heart valve of claim 15, wherein the stent includes a firstdiameter at a first location, wherein the stent includes a seconddiameter at a second location, the second location being offset towardthe outflow end of the stent from the first location, and wherein thestent includes a third diameter at a third location, the third locationbeing disposed between the first location and the second location, andwherein the third diameter is less than the first diameter and thesecond diameter.
 19. The prosthetic heart valve of claim 15, furthercomprising an annular skirt disposed radially between and the struts andthe leaflet assembly, wherein the skirt is sutured to the struts.
 20. Aprosthetic heart valve comprising: a self-expanding frame having aninflow end, an outflow end, and a plurality of interconnected struts,the frame comprising: a first row of cells disposed proximate theoutflow end, wherein sides of each cell in the first row of cells touchadjacent cells of the first row of cells; a second row of cells disposedcloser to the inflow end portion than the first row of cells, whereinthe second row of cells comprises a larger number of smaller cells thanthe first row of cells; and a third row of cells formed between portionsof cells of the first row of cells such that sides of cells of the thirdrow of cells do not touch adjacent cells of the third row of cells, andwherein inflow ends of each cell of the third row of cells and inflowends of each cell of the first row of cells are equidistant from theinflow end of the frame; and a leaflet assembly coupled to the frame andhaving a plurality of leaflets, wherein the leaflets are configured toallow blood to flow through the prosthetic heart valve in one directionfrom the inflow end portion to the outflow end portion of the frame.